Molar Pregnancy

Molar Pregnancy: Signs, Symptoms, Causes & Treatments

The loss of a pregnancy is always a very difficult and trying time for a woman and her family.

When I then go on and explain a pregnancy complication to a patient and partner, and I hear the patient say– “I didn’t even know this condition existed! How can this possibly happen to me if I have never met anyone else with this problem!” – It does break my heart even more. If one has never even heard about an illness or pregnancy condition, one has no way to prepare for the remote but possible chance of being affected by it and in no way can emotionally prepare for it.

Most women are aware nowadays that almost 1 in 4 early pregnancies, can result in early miscarriage.  It is a tough and disappointing time for women and their families when this happens, but most women are aware and had an opportunity to be somewhat prepared for this emotionally draining and sad outcome.

What many women might not know or might not have ever heard about is a pregnancy complication less talked about:

It’s called a MOLAR pregnancy. 

What is a Molar pregnancy?

It’s a pregnancy complication that is much rarer than a miscarriage and only affects around 1:1000 pregnancies. It is called Hydatiform Molar pregnancy and it occurs when something goes wrong right at the beginning of conception.


In a COMPLETE MOLAR pregnancy, an egg without genetic material is fertilised by a sperm. As there is only one set of genetic information, a fetus never develops. However, the placental tissue shows much faster growth than usual. It also produces real high levels of pregnancy hormones. This often causes much more morning sickness in the woman, sometimes requiring hospital admission. On the early pregnancy ultrasound, there is no fetus and no heartbeat visible, and the pregnancy tissue shows an abnormal growth pattern.

In a PARTIAL MOLAR pregnancy, two sperm enter a normal egg, but instead of forming twins a fetus that is not healthy develops. As the fetus/baby has the wrong genetic information, it cannot grow and survive. Part of the placenta develops normally and part of the placenta shows the fast overgrowth pattern which is not normal for an early pregnancy.

Both those pregnancy complications are part of the GESTATIONAL TROPHOPLASTIC DISEASE family.


Most women are diagnosed early, as they have vaginal bleeding in early pregnancyvery high pregnancy hormone levels and severe morning sickness. An early pregnancy ultrasound is then organised and shows the quite unusual growth pattern of the placenta without a fetus or heartbeat.

The Risk Factors.

As mentioned above, the cause for a hydatiform molar pregnancy is a problem with genetic information. However certain factors increase the chance of molar pregnancy:

  • Having had a previous molar pregnancy makes the chance of it happening again 1 in 100. However, 99 out of 100 women will have a healthy pregnancy in the future!
  • Being very young when falling pregnant < 20 years of age or having a pregnancy > 40 years of age.
  • Having certain nutritional deficiencies, like a lack of carotene in one’s diet increases the risk.
  • Being of Southeast Asian or Mexican descent.


The treatment for a molar pregnancy is dilatation and evacuation of the uterus, commonly also called “suction curette”. The pathologist then looks at the pregnancy tissue and advises if there is a molar pregnancy or just a “usual” miscarriage.

The majority of molar pregnancies are treated and cured by just passing the pregnancy tissue naturally or having the above-mentioned suction curette.

However, in approx. 10% of cases, small amounts of this abnormal tissue could persist in the uterus and grow into the uterine lining or very rarely spread to other organs. This is called PERSISTENT GESTATIONAL TROPHOBLASTIC DISEASE.

That’s why it is very important to take this diagnosis seriously and follow up on pregnancy hormone levels over the course of weeks and months to follow.


In Victoria and Queensland, Molar pregnancy registers have been established, which assist women in this tough time. They deliver high quality and safe care and follow up. In other states, it might be a PUBLIC hospital or a female obstetrician and gynaecologist who guides a patient through the months after diagnosis.

As follow up for PARTIAL MOLAR pregnancy the pregnancy hormone level usually gets checked until it has normalised again, which usually takes a few weeks. It’s important NOT to fall pregnant at that time. For a Complete Molar pregnancy, things can drag on a little longer as not only will the hormone levels be monitored to reaching 0, but women are also advised to not fall pregnant again for 4-6 months after which time the hormone levels are measured monthly. Again, it is very important TO NOT FALL PREGNANT again in that time, as a new pregnancy would make the hormone level rise again. It’s then unclear what’s causing the higher level in the recent molar pregnancy or the new conception.

Should the hormone levels not drop as expected, the specialist will be recommending further testing and treatment if required. The most common form of further treatment is called Methotrexate, a very well tolerated chemotherapy drug that has been used in treatment for Molar Pregnancy for decades with excellent outcomes. THE CURE RATE FOR MOLAR PREGNANCY IS EXCELLENT! It is usually 100% and even in case of persistent disease and spread it is 98-100%.


Usually, women can use hormonal contraception to avoid falling pregnant, guided by the practitioner’s advice who is caring for them. Initially, women might be asked to use barrier contraception/condoms only. Until the hormone level has fully dropped and normalised, you will be advised NOT to have an intrauterine device (Mirena IUD or Copper IUD) fitted as the risk of injuring the uterus is higher immediately after having passed the tissue of a molar pregnancy.


Being diagnosed with a MOLAR pregnancy is usually a very tough time for the woman, her partner, and the family. Not only do they mourn the loss of a pregnancy, but also do they have to delay their plans for another pregnancy by several months.

Furthermore, the concern about possibly having to deal with ongoing issues and treatment if the hormone levels don’t drop is another factor that can weigh heavily on women.

It is important to encourage women to reach out, to family and health care providers if the loss and diagnosis become overwhelming and ongoing support is required. Most importantly we must assure women: it’s not their fault!  Nothing they have or haven’t done has caused this complication, they have not brought it upon themselves.

It’s also important to know that most women will go on and have another healthy pregnancy!

Have a question about Molar pregnancy?

If you have experienced a Molar pregnancy or consider yourself at high risk, you may have some questions about what this means for your fertility, or concerns about getting pregnant again. Having an Obstetrician & Gynaecologist alongside you during the early days of your pregnancy will reduce your concerns and alleviate any worries that you are experiencing.

Dr Caroline Hoggenmueller can provide you with specialist support and advice during this time. When you do decide to try to become pregnant and subsequent pregnancy is confirmed, Dr Hoggenmueller will be there to monitor your health and the progress of your pregnancy. She consults in Melbourne, Bundoora and Heidelberg, and can be available 24 hours, 7 days a week for women with high-risk pregnancies.