HCG Levels After IVF Frozen Transfer: A Detailed Guide

IVF frozen embryo transfer is one of the solutions available to couples who are looking to have a baby.

The HCG hormones appear in the pregnant woman’s blood, indicating pregnancy. In this article, we discuss HCG levels in pregnancy during IVF frozen embryo transfer.

What is HCG?

HCG/hCG stands for human chorionic gonadotropin. It is a hormone that is produced by the placenta during pregnancy. The HCG is usually released by the body approximately 11 days after successful conception.

Once released into the body, the HCG triggers the release of larger quantities of hormones like progesterone and oestrogen, which are responsible for the thickening of the uterine lining during pregnancy.

It is when HCG, progesterone and oestrogen are at the right levels in the body that there is a viable pregnancy.

How is HCG produced in the body during natural pregnancy?

Every month, the female body releases an egg, which, when fertilised, moves down through the fallopian tube to the uterus.

There, the fertilised egg attaches itself to the wall of the uterus, resulting in the formation of the placenta. The placenta then releases the HCG hormone to create a conducive environment where the embryo can thrive.

HCG levels can be observed both in the urine and the blood during testing.

From Day 10-11 of the pregnancy, the HCG level will rise and be at its highest around Week 10. Then, the HCG levels will start to taper down for the rest of the pregnancy.

The IVF procedure

In vitro fertilisation (IVF) is a medical procedure designed to help women and female-bodied individuals get pregnant when natural conception isn’t possible.

It is a process of assisted reproduction, where the egg is fertilised outside of the body in the lab. This embryo is then transferred into the uterus, completing the remainder of the pregnancy cycle.

In a conventional IVF procedure, fertility-boosting medicines are given to the woman to increase the number of eggs produced by the body.

These eggs are retrieved either through follicular aspiration surgery or a pelvic laparoscopy. If viable eggs cannot be obtained, donor eggs may be suggested.

The highest quality eggs will be chosen and inseminated with either the male partner’s sperm or the donor sperm selected by the woman/couple.

The eggs remain inside a specialised chamber, and within a few hours, fertilisation occurs. An intracytoplasmic sperm injection (ICSI) is sometimes used to increase the chances of successful fertilisation.

If the fertilised egg starts to develop quickly, within 3-5 days, the embryo will be implanted into the woman’s womb, and the pregnancy will be monitored.

The IVF frozen embryo transfer

One of the challenges with conventional IVF treatments is the different rates at which the embryo develops outside the body, and the pregnancy hormone is produced within the woman’s body.

In natural conception, all pregnancy hormones rise at a rate that is safe and conducive for the developing embryo. This is because the menstrual cycle changes naturally to accommodate conception.

However, in IVF procedures, both the woman’s ovaries and the fertilisation of the eggs outside the body are stimulated. Therefore, the woman’s menstrual cycle is not aligned with her typical cycle.

Due to the overstimulation of the ovaries, oestrogen rates rise too quickly and, in turn, increase the progesterone levels too fast. When this happens, it affects how quickly the endometrial lining develops.

A healthy endometrial/uterine lining is essential for the development of the placenta and the production of HCG hormone.

But because the woman’s menstrual cycle is overstimulated, the growth rate in the uterine lining may not be correct to support the embryo at its current stage of development. This can actually increase the risk of pregnancy failure after implantation.

That is why, these days, doctors recommend IVF frozen embryo transfer (FET). In this procedure, the woman undergoes an IVF treatment at first.

However, rather than implanting the embryo into her body within a few days, the embryo is frozen and kept inside a specially-designed facility.

The fertility doctors monitor the woman’s hormone levels and wait for the menstrual cycle to return to normal. Once the body recovers from the IVF, the frozen embryo is transferred into the woman’s body.

This short gap given between IVF and implantation increases the chances of a successful pregnancy significantly.

Some studies show that IVF frozen transfer has success rates as close to natural conceptions, with fewer rates of miscarriage and reduced foetal developmental problems.

Promising HGC levels for pregnancy after IVF frozen embryo transfer

In a conventional IVF procedure, additional HCG trigger shots are given to increase the successful implantation of the embryo. But in a frozen embryo transplant, these trigger shots are not provided.

Instead, in an IVF frozen embryo transplant, the doctors wait for about 2 weeks to monitor the rise in HCG levels. After two weeks, the beta hCG test is done to check the HCG levels in the woman’s bloodstream.

Here are the typical levels of HCG that patients can expect after an IVF FET. All numbers are calculated at milli-international units per millilitre (mIU/ml):

• </= 5 mIU/ml – Negative result/No pregnancy
• =/> 25 mIU/ml – Positive result/Pregnancy

Typically, in a successful pregnancy, the HCG levels double within two days of the first beta hCG test having been done. Therefore, if Week 2 revealed an HCG level of 25 mIU/ml two days after the test, the level of HCG should ideally be 50 mIU/ml.

The HCG levels by week can also indicate factors like the risk of miscarriage and the possibility of multiple pregnancies.

For example, some studies show that if HCG levels are <85 mIU/ml on Day 13, then women have an 89% risk of miscarriage within the first trimester.

On the other hand, Day 13 pregnancies with HCG levels >386 mU/mL have been found to have up to 91% success rate of safe, live births.

Similarly, doctors also monitor HCG levels after IVF FET to check whether the foetus is singleton or multiples. One study indicated these Day 13 HCG levels – 339 mIU/mL (singleton) and 544 mIU/mL (multiples).

However, in most cases, doctors tend to look at how the HCG levels rise on a day-to-day basis. Ideally, if by Day 17, after the IVF frozen embryo transfer, the HCG value is above 200 mIU/mL, it is considered a promising pregnancy.

Each woman’s body is different and responds differently after IVF-frozen embryo transfer.

The HCG levels by week may vary between patients, and the fertility doctor will be able to provide further information about the correct HCG levels in pregnancy for each patient.

In conclusion 

Birla Fertility & IVF is one of India’s premier fertility centres, with years of experience helping couples conceive healthy babies.

Our state-of-the-art IVF frozen embryo transfer facility is fully-equipped to help you successfully and safely conceive a child through IVF.

Our team will monitor your cycle, egg health, HCG levels and pregnancy and support you throughout this important journey. Feel free to speak to our fertility doctors today by visiting your nearest BFI centre or booking an appointment.

FAQs

How long after FET implantation does HCG rise?

Typically, HCG levels become traceable in the blood around 2 weeks after the IVF FET implantation. Although, minute traces may be detected after Day 11 too. A beta hCG test can confirm the level of HCG in the body.

What is a good HCG after FET?

A good HCG level after FET is =/> 25 mIU/ml, and this should double every two days after the previous beta hCG test.

Do frozen embryos take longer to implant?

Not necessarily. But waiting to let the woman’s menstrual cycle stabilise before implanting the embryos can give her the highest chance of having a successful pregnancy and conceiving a healthy baby.