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Prevention, Recognition, and Treatment of Hydatidiform Molar Pregnancies

by Dr. Geoffrey Sher on July 11, 2016

A hydatidiform molar pregnancy happens when tissue that normally forms the placenta instead becomes a growth, that triggers symptoms of pregnancy. A hydatidiform mole is a benign tumor of the root system (trophoblast) of the embryo which under normal conditions develops into the placenta which connects the baby to the mother. About 1 out of 2,000 women with early pregnancy symptoms will have a molar pregnancy. It is approximately twice as common in women of Asian descent. The condition requires urgent treatment and follow-up to avoid serious complications that can involve invasion of the uterine wall and surrounding structures (i.e. invasive mole or chorioadenoma destruens) or malignant change (choriocarcinoma).

In more than 25% of early pregnancies there will be some vaginal bleeding. About one half of these end up by miscarrying. In the remaining half, the bleeding subsides and the pregnancy continues to evolve such that most will culminate in a healthy live birth. In less than 2% of cases of such bleeding the cause of early pregnancy bleeding is hydatidiform mole (molar) pregnancy. With molar pregnancy, the roots of the trophoblast (chorionic villi) undergo cystic degeneration and when the woman bleeds, these cystic structures are passed in dark blood, giving rise to the common description of “white currents floating in red currant jelly”.

In non-molar pregnancies, an inevitable miscarriage almost invariably presents with flattening or declining blood pregnancy hormone (i.e. hCG) levels. Conversely, with hydatidiform mole the blood hCG concentration is usually elevated continues to rise. In addition, the woman will often experience exaggerated pregnancy symptoms (e.g. pernicious vomiting, very frequent urination and bloating) and lower abdominal cramping. On examination, she will often be found to have a markedly elevated blood pressure. On abdominal or vaginal examination here uterus is commonly enlarged beyond that which can be explained on the basis of the duration of pregnancy. Ultrasound examination usually (but not invariably) reveals a hazy, so called “snow storm pattern” and the absence of a conceptus.

There are two types of hydatidiform mole, complete or partial

  • Complete Hydatidiform mole:  Like normal pregnancies the complete mole has 46 chromosomes (two sets of 23), i.e. it is diploid.. However unlike with normal fertilization where one set of chromosomes comes from the mother and the other set from the father, with a complete molar pregnancy both sets of chromosomes come from the father. This is the result from duplication of a sperm’s chromosomes after it has fertilized an “inactive egg”. Since an embryo that has a YY karyotype is not viable, the chromosome gender of the molar pregnancy is invariably XX (female). Accordingly, if with IVF, one avoids transferring an embryo that by preimplantation genetic diagnosis (PGD) is found to be female (XX) and selectively transfers only male (XY) embryos the possibility of a complete molar pregnancy can be virtually eliminated. A complete molar pregnancy can result from fertilization of an “inactive egg” by 2 separate spermatozoa. Injection of a single sperm by ICSI avoids the latter from occurring altogether. In <10% of cases a complete Hydatidform molar pregnancy can be inherited due to a mutation (not yet clearly identified) involving chromosome 19. In such cases molar pregnancies can occur repetitively and the mole can have an XX or an XY chromosomal configuration. It should be borne in mind however, that not all repetitive molar pregnancies are due to this mutation. Complete molar pregnancies can also run in families (e.g. in sisters). The true incidence of this genetic mutation is still unknown. This situation cannot be identified by PGD.
  • Partial (placental) molar pregnancies are usually triploid [i.e. their cells contain three sets of (23each) chromosomes]. Thus with partial moles, the sex chromosome configuration will be XXY or XYY. Partial Hydatidform molar can therefore be avoided through selectively transferring embryos where through PGD triploidy has been excluded.

More than 80% of molar pregnancies are benign (noncancerous). Treatment involves complete emptying of the uterus as soon as the diagnosis is made. Even in cases where a spontaneous passage of the molar tissue appears to be complete. The reason is to avoid the development of an invasive mole (chorioadenoma destruens), where the uterine wall is permeated by remaining tissue and to limit the development of choriocarcinoma (where the molar tissue becomes malignant). In the vast majority of properly managed cases however, outcome after treatment is usually excellent. Close follow-up with serial quantitative blood hCG testing, ultrasound and/or Magnetic Resonance Imaging (MRI) is essential. After treatment, the woman must use very effective contraception for at least 6 to 12 months so as to avoid pregnancy in order to allow for proper follow-up.

Choriocarcinoma is a very malignant tumor that invades the uterus and can spread rapidly via the blood system to bone, lungs, brain and other sites. Fortunately choriocarcinoma does respond well to hysterectomy and removal of ovaries with aggressive, selective chemotherapy.

While Molar pregnancy is not commonly seen in patients undergoing IVF, it does occur and the vigilant doctor should always be on the look-out for it. As indicated, in cases in which a woman seeking IVF has a family history of the condition or has had a prior molar pregnancy herself, PGD can provide an efficient way to all but prevent this condition from occurring.

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  • Erica - September 17, 2018 reply

    I went through IVF and had 2 males and 2 female embryos. Last December we only had the two females left. We transferred one female and it ended up being a molar pregnancy. What are the chances my last female embryo will also result in a molar pregnancy? We have no family history of this that I know of.

    Dr. Geoffrey Sher

    Dr. Geoffrey Sher - September 17, 2018 reply

    Highly unlikely!
    A hydatidiform molar pregnancy happens when tissue that normally forms the placenta instead becomes a growth, that triggers symptoms of pregnancy. A hydatidiform mole is a benign tumor of the root system (trophoblast) of the embryo which under normal conditions develops into the placenta which connects the baby to the mother. About 1 out of 2,000 women with early pregnancy symptoms will have a molar pregnancy. It is approximately twice as common in women of Asian extraction.The condition requires urgent treatment and follow-up to avoid serious complications that can involve invasion of the uterine wall and surrounding structures (i.e. invasive mole or chorioadenoma destruens) or malignant change (choriocarcinoma)

    In more than 25% of early pregnancies there will be some vaginal bleeding. About one half of these end up by miscarrying. In the remaining half, the bleeding subsides and the pregnancy continues to evolve such that most will culminate in a healthy live birth. In less than 2% of cases of such bleeding the cause of early pregnancy bleeding is hydatidiform mole (molar) pregnancy. With molar pregnancy, the roots of the trophoblast (chorionic villi) undergo cystic degeneration and when the woman bleeds, these cystic structures are passed in dark blood, giving rise to the common description of “white currents floating in red currant jelly”.

    In non-molar pregnancies, an inevitable miscarriage almost invariably presents with flattening or declining blood pregnancy hormone (i.e. hCG) levels. Conversely, with hydatidiform mole the blood hCG concentration is usually elevated continues to rise. In addition, the woman will often experience exaggerated pregnancy symptoms (e.g. pernicious vomiting, very frequent urination and bloating) and lower abdominal cramping. On examination, she will often be found to have a markedly elevated blood pressure. On abdominal or vaginal examination here uterus is commonly enlarged beyond that which can be explained on the basis of the duration of pregnancy. Ultrasound examination usually (but not invariably) reveals a hazy, so called “snow storm pattern” and the absence of a conceptus.

    There are two types of hydatidiform mole, complete or partial

    • Complete Hydatidiform mole: Like normal pregnancies the complete mole has 46 chromosomes (two sets of 23), i.e. it is diploid.. However unlike with normal fertilization where one set of chromosomes comes from the mother and the other set from the father, with a complete molar pregnancy both sets of chromosomes come from the father. This is the result from duplication of a sperm’s chromosomes after it has fertilized an “inactive egg”. Since an embryo that has a YY karyotype is not viable, the chromosome gender of the molar pregnancy is invariably XX (female). Accordingly, if with IVF, one avoids transferring an embryo that by preimplantation genetic diagnosis (PGD) is found to be female (XX) and selectively transfers only male (XY) embryos the possibility of a complete molar pregnancy can be virtually eliminated. A complete molar pregnancy can result from fertilization of an “inactive egg” by 2 separate spermatozoa. Injection of a single sperm by ICSI avoids the latter from occurring altogether. In <10% of cases a complete Hydatidform molar pregnancy can be inherited due to a mutation (not yet clearly identified) involving chromosome 19. In such cases molar pregnancies can occur repetitively and the mole can have an XX or an XY chromosomal configuration. It should be borne in mind however, that not all repetitive molar pregnancies are due to this mutation. Complete molar pregnancies can also run in families (e.g. in sisters). The true incidence of this genetic mutation is still unknown. This situation cannot be identified by PGD.

    • Partial (placental) molar pregnancies are usually triploid [i.e. their cells contain three sets of (23each) chromosomes]. Thus with partial moles, the sex chromosome configuration will be XXY or XYY. Partial Hydatidform molar can therefore be avoided through selectively transferring embryos where through PGD triploidy has been excluded.
    More than 80% of molar pregnancies are benign (noncancerous). Treatment involves complete emptying of the uterus as soon as the diagnosis is made. Even in cases where a spontaneous passage of the molar tissue appears to be complete. The reason is to avoid the development of an invasive mole (chorioadenoma destruens), where the uterine wall is permeated by remaining tissue and to limit the development of choriocarcinoma (where the molar tissue becomes malignant). In the vast majority of properly managed cases however, outcome after treatment is usually excellent. Close follow-up with serial quantitative blood hCG testing, ultrasound and/or Magnetic Resonance Imaging (MRI) is essential. After treatment, the woman must use very effective contraception for at least 6 to 12 months so as to avoid pregnancy in order to allow for proper follow-up.
    Choriocarcinoma is a very malignant tumor that invades the uterus and can spread rapidly via the blood system to bone, lungs, brain and other sites. Fortunately choriocarcinoma does respond well to hysterectomy and removal of ovaries with aggressive, selective chemotherapy.
    While Molar pregnancy is not commonly seen in patients undergoing IVF, it does occur and the vigilant doctor should always be on the look-out for it. As indicated, in cases where a woman seeking IVF has a family history of the condition or has had a prior molar pregnancy herself, PGD can provide an efficient way to all but prevent this condition from occurring.

    Geoff Sher
    800-780-7437

  • Jennifer - January 28, 2017 reply

    Hi Dr Sher

    I’m a 37 year old female with a unicornate uterus (left tube and side functional only with non communicating right horn). I’m also a poor responder in ivf… on a good protocol tend to get about 9 eggs and 2 or 3 day 5 blasts. My husband and I have been ttc since 2009. In 2012 I had a natural pregnancy but bled very early and given the high hcg levels I remember the doctor commenting about a molar. In 2015 I had another natural pregnancy which led to a missed miscarriage at 11 weeks. The tests showed he was a little boy and had triploidy.
    We have done 4 ivf cycles since 2013 and only ever had 1 positive which resulted in a chemical pregnancy in November 2016.

    Do you think there is a link between the molar and the triploidy pregnancies? Is there something specific I should test for or any specific protocol you would recommend for our next ivf?

    Thank you very much

    Dr. Geoffrey Sher

    Dr. Geoffrey Sher - January 28, 2017 reply

    I don’t think your unicornuate uterus is relevant to your reproductive dysfunction. In my opinion, the protocol used for ovarian stimulation, against the backdrop of age, and ovarian reserve are the drivers of egg quality and egg quality is the most important factor affecting embryo “competency”.
    Women who (regardless of age) have DOR have a reduced potential for IVF success. Much of this is due to the fact that such women tend to have increased production of LH biological activity which can result in excessive LH-induced ovarian male hormone (predominantly testosterone) production which in turn can have a deleterious effect on egg/embryo “competency”.

    While it is presently not possible by any means, to reverse the effect of DOR, certain ovarian stimulation regimes, by promoting excessive LH production (e.g. short agonist/Lupron- “flare” protocols, clomiphene and Letrozole), can in my opinion, make matters worse. Similarly, the amount/dosage of certain fertility drugs that contain LH/hCG (e.g. Menopur) can have a negative effect on the development of the eggs of older women and those who have DOR and should be limited.I try to avoid using such protocols/regimes (especially) in women with DOR, favoring instead the use of the agonist/antagonist conversion protocol (A/ACP), a modified, long pituitary down-regulation regime, augmented by adding supplementary human growth hormone (HGH). I further recommend that such women be offered access to embryo banking of PGS (next generation gene sequencing/NGS)-selected normal blastocysts, the subsequent selective transfer of which by allowing them to capitalize on whatever residual ovarian reserve and egg quality might still exist and thereby “make hay while the sun still shines” could significantly enhance the opportunity to achieve a viable pregnancy

    Please visit my new Blog on this very site, http://www.DrGeoffreySherIVF.com, find the “search bar” and type in the titles of any/all of the articles listed below, one by one. “Click” and you will immediately be taken to those you select. Please also take the time to post any questions or comments with the full expectation that I will (as always) respond promptly.

    • Controlled Ovarian Stimulation (COS) for IVF: Selecting the ideal protocol
    • IVF: Factors Affecting Egg/Embryo “competency” during Controlled Ovarian Stimulation(COS)
    • The Fundamental Requirements For Achieving Optimal IVF Success
    • Ovarian Stimulation for IVF using GnRH Antagonists: Comparing the Agonist/Antagonist Conversion Protocol.(A/ACP) With the “Conventional” Antagonist Approach
    • Anti Mullerian Hormone (AMH) Measurement to Assess Ovarian Reserve and Design the Optimal Protocol for Controlled Ovarian Stimulation (COS) in IVF.
    • The “Biological Clock” and how it should Influence the Selection and Design of Ovarian Stimulation Protocols for IVF.
    • A Rational Basis for selecting Controlled Ovarian Stimulation (COS) protocols in women with Diminished Ovarian Reserve (DOR)
    • Diagnosing and Treating Infertility due to Diminished Ovarian Reserve (DOR)
    • Controlled Ovarian Stimulation (COS) in Older women and Women who have Diminished Ovarian Reserve (DOR): A Rational Basis for Selecting a Stimulation Protocol
    • Human Growth Hormone Administration in IVF: Does it Enhances Egg/Embryo Quality and Outcome?
    • The BCP: Does Launching a Cycle of Controlled Ovarian Stimulation (COS). Coming off the BCP Compromise Response?
    • Blastocyst Embryo Transfers should be the Standard of Care in IVF
    • Frozen Embryo Transfer (FET) versus “Fresh” ET: How to Make the Decision
    • Frozen Embryo Transfer (FET): A Rational Approach to Hormonal Preparation and How new Methodology is Impacting IVF.
    • Staggered IVF: An Excellent Option When. Advancing Age and Diminished Ovarian Reserve (DOR) Reduces IVF Success Rate
    • Embryo Banking/Stockpiling: Slows the “Biological Clock” and offers a Selective Alternative to IVF-Egg Donation.
    • Preimplantation Genetic Testing (PGS) in IVF: It should be Used Selectively and NOT be Routine.
    • Preimplantation Genetic Sampling (PGS) Using: Next Generation Gene Sequencing (NGS): Method of Choice.
    • PGS in IVF: Are Some Chromosomally Abnormal Embryos Capable of Resulting in Normal Babies and Being Wrongly Discarded?
    • PGS and Assessment of Egg/Embryo “competency”: How Method, Timing and Methodology Could Affect Reliability
    • Treating Out-of-State and Out-of-Country Patients at Sher-IVF in Las Vegas:
    • Traveling for IVF from Out of State/Country–
    • A personalized, stepwise approach to IVF
    • How Many Embryos should be transferred: A Critical Decision in IVF.
    • The Role of Nutritional Supplements in Preparing for IVF
    • Premature Luteinization (“the premature LH surge): Why it happens and how it can be prevented.
    • IVF Egg Donation: A Comprehensive Overview

    I invite you to arrange to have a Skype or an in-person consultation with me to discuss your case in detail. If you are interested, please contact Julie Dahan, at:
    Email: Julied@sherivf.com
    OR
    Phone: 702-533-2691
    800-780-7437
    I also suggest that you access the 4th edition of my book ,”In Vitro Fertilization, the ART of Making Babies”. It is available as a down-load through http://www.Amazon.com or from most bookstores and public libraries.

  • Angela lam - September 9, 2016 reply

    I am 37 years old, Chinese. 8 weeks pregnant, I went for a check up and they couldn’t fine a heartbeat, that was 3weeks ago and a d&c was performed 2 days after that. I went back to the hospital for a check up 2 weeks after, and they told me they found out it was a molar pregnancy, the doctor was too lazy to explain what it was and I was asked to google it online myself. They took blood test and I am suppose to go back tomorrow to have another blood test. I have been reading a lot of articles and past from support groups online and read that Asian has higher chance of getting a molar pregnancy, after talking to my family in Hong Kong and hearing a few cases, they all have a 2nd D& C about a week after the 1st, and they all recovered, waited for 6 months to 1 year with test every 3 months, got pregnant again and gave birth to healthy babies. I can’t help to think that if I should have another D& C now to make sure its clean. I keep thinking why I should be sitting here to wait for it to turn into cancer. My question is, was the 2nd D&c they did to all the patients in Hong Kong necessary? They were being monitored very closely days after the 1st. In my case, it’s been over 3 week now and I still didn’t get any test results from my OBGYN. Should I be asking a 2nd opinion from someone else? I tried to look for another OBGYN in the city but all the specialists were either not covered by my insurance plan, too occupied until November, or some of them said it’s too much liability to take me now after the miscarriage. I am stuck with this group of doctors that I do not trust, I see different doctors and different nurse every time I have been there, and none of them know what I supposed to be doing each time, they would ask me back each time. Do you have any suggestions for me?

    Dr. Geoffrey Sher

    Dr. Geoffrey Sher - September 9, 2016 reply

    What you describe does not sound right! You need and deserve appropriate counseling.

    A hydatidiform molar pregnancy happens when tissue that normally forms the placenta instead becomes a growth, that triggers symptoms of pregnancy. A hydatidiform mole is a benign tumor of the root system (trophoblast) of the embryo which under normal conditions develops into the placenta which connects the baby to the mother. About 1 out of 2,000 women with early pregnancy symptoms will have a molar pregnancy. It is approximately twice as common in women of Asian extraction.The condition requires urgent treatment and follow-up to avoid serious complications that can involve invasion of the uterine wall and surrounding structures (i.e. invasive mole or chorioadenoma destruens) or malignant change (choriocarcinoma)

    In more25% of early pregnancies there will be some vaginal bleeding. About one half of these end up by miscarrying. In the remaining half, the bleeding subsides and the pregnancy continues to evolve such that most will culminate in a healthy live birth. In less than 2% of cases of such bleeding the cause of early pregnancy bleeding is hydatidiform mole (molar) pregnancy. With molar pregnancy, the roots of the trophoblast (chorionic villi) undergo cystic degeneration and when the woman bleeds, these cystic structures are passed in dark blood, giving rise to the common description of “white currents floating in red currant jelly”.

    In non-molar pregnancies, an inevitable miscarriage almost invariably presents with flattening or declining blood pregnancy hormone (i.e. hCG) levels. Conversely, with hydatidiform mole the blood hCG concentration is usually elevated continues to rise. In addition, the woman will often experience exaggerated pregnancy symptoms (e.g. pernicious vomiting, very frequent urination and bloating) and lower abdominal cramping. On examination, she will often be found to have a markedly elevated blood pressure. On abdominal or vaginal examination here uterus is commonly enlarged beyond that which can be explained on the basis of the duration of pregnancy. Ultrasound examination usually (but not invariably) reveals a hazy, so called “snow storm pattern” and the absence of a conceptus.

    There are two types of hydatidiform mole, complete or partial

    • Complete Hydatidiform mole: Like normal pregnancies the complete mole has 46 chromosomes (two sets of 23), i.e. it is diploid.. However unlike with normal fertilization where one set of chromosomes comes from the mother and the other set from the father, with a complete molar pregnancy both sets of chromosomes come from the father. This is the result from duplication of a sperm’s chromosomes after it has fertilized an “inactive egg”. Since an embryo that has a YY karyotype is not viable, the chromosome gender of the molar pregnancy is invariably XX (female). Accordingly, if with IVF, one avoids transferring an embryo that by preimplantation genetic diagnosis (PGD) is found to be female (XX) and selectively transfers only male (XY) embryos the possibility of a complete molar pregnancy can be virtually eliminated. A complete molar pregnancy can result from fertilization of an “inactive egg” by 2 separate spermatozoa. Injection of a single sperm by ICSI avoids the latter from occurring altogether. In <10% of cases a complete Hydatidform molar pregnancy can be inherited due to a mutation (not yet clearly identified) involving chromosome 19. In such cases molar pregnancies can occur repetitively and the mole can have an XX or an XY chromosomal configuration. It should be borne in mind however, that not all repetitive molar pregnancies are due to this mutation. Complete molar pregnancies can also run in families (e.g. in sisters). The true incidence of this genetic mutation is still unknown. This situation cannot be identified by PGD.

    • Partial (placental) molar pregnancies are usually triploid [i.e. their cells contain three sets of (23each) chromosomes]. Thus with partial moles, the sex chromosome configuration will be XXY or XYY. Partial Hydatidform molar can therefore be avoided through selectively transferring embryos where through PGD triploidy has been excluded.
    More than 80% of molar pregnancies are benign (noncancerous). Treatment involves complete emptying of the uterus as soon as the diagnosis is made. Even in cases where a spontaneous passage of the molar tissue appears to be complete. The reason is to avoid the development of an invasive mole (chorioadenoma destruens), where the uterine wall is permeated by remaining tissue and to limit the development of choriocarcinoma (where the molar tissue becomes malignant). In the vast majority of properly managed cases however, outcome after treatment is usually excellent. Close follow-up with serial quantitative blood hCG testing, ultrasound and/or Magnetic Resonance Imaging (MRI) is essential. After treatment, the woman must use very effective contraception for at least 6 to 12 months so as to avoid pregnancy in order to allow for proper follow-up.
    Choriocarcinoma is a very malignant tumor that invades the uterus and can spread rapidly via the blood system to bone, lungs, brain and other sites. Fortunately choriocarcinoma does respond well to hysterectomy and removal of ovaries with aggressive, selective chemotherapy.
    While Molar pregnancy is not commonly seen in patients undergoing IVF, it does occur and the vigilant doctor should always be on the look-out for it. As indicated, in cases where a woman seeking IVF has a family history of the condition or has had a prior molar pregnancy herself, PGD can provide an efficient way to all but prevent this condition from occurring.

    Good luck!

    Geoff Sher

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