When we think about pregnancy, we hardly imagine how many different combinations our body has to make for the dream to come true. The beginning of pregnancy can be a mystery for many women. So how about uncovering what happens at the start of pregnancy and what the endometrium has to do with all of this?

What Is the Endometrium

Everything starts with menstruation. The endometrium from the previous cycle is shed by the body. But what exactly is the endometrium? The endometrium is a layer that grows every cycle inside the uterus and will initially house the embryo. After it is shed during menstruation, it forms again under the influence of hormones in the next cycle1.

What Is the Function of the Endometrium

The endometrium is nothing more than a thick, blood-filled layer inside the uterus that houses the embryo in its earliest stages. The growth of the endometrium is stimulated by hormones such as progesterone and estrogen. This hormone is released by the ovaries to stimulate the growth and maturation of follicles, so the woman can ovulate and become pregnant.

The endometrium is like a blood sponge inside the uterus. It is ready to receive the egg fertilized by the sperm, nestle it, and keep it safe for its development until the placenta forms.

Ideal Endometrium for Pregnancy

Anyone who has had preventive ultrasounds has probably had a report in hand saying something about the endometrium, right? It is necessary for pregnancy to happen, because this is where the embryo attaches to grow and for the pregnancy to progress.

But not every endometrium can host the baby2. There is an ideal thickness for this to happen. The ideal to shelter the baby is from 8mm and up. For the embryo to attach correctly, the endometrium needs to have the ideal thickness.

And When the Endometrium Is Thin?

Thicknesses below 5mm are inappropriate for pregnancy to occur because there isn’t enough depth for the implantation of the baby. But not all is lost for those who suffer from a thin endometrium3. The doctor may prescribe medications to help it thicken, making pregnancy possible.

How to Make the Endometrium Thicker?

Several medications can be used to lend a helping hand. A force of nature to help thicken the endometrium is using yam. It helps stimulate the endometrium’s growth in the pre-ovulatory phase. While the eggs are maturing, the endometrium also grows at the same time. For many, it is difficult to include yam in their diet every day, so a good option is yam capsules.

Another important aspect for pregnancy is the endometrial layers. The layers are sheets formed by blood. An endometrium with three layers (trilaminar) is ideal for proper embryo implantation.

The trilaminar endometrium is easily verified on a gynecological ultrasound. There are women who simply do not get pregnant because they do not have a good endometrium. They ovulate every cycle, but their thin endometrium cannot support a pregnancy. That’s why monitoring by ultrasound is necessary.

Usually, the endometrium is examined in the post-ovulatory or luteal phase, when it tends to become thicker. If there was ovulation and fertilization of the egg, it grows even more. On the ultrasound report the information comes through the endometrial echo, which are the measurements of the endometrium.

Difficulty in Making the Endometrium Thicker

Women who have trouble balancing estrogen have difficulty thickening the endometrium naturally. Women with low progesterone may be able to thicken the endometrium, but do not have enough hormone to hold it until the embryo is attached. That’s why a minimum number of luteal phase days is needed, to give the zygote time to reach the back of the uterus where the endometrium is. A minimum of 12 days of luteal phase is required for pregnancy to happen. If a woman has an extremely short cycle, her doctor should assess her luteal phase and check if progesterone levels are adequate.

Also, in the post-ovulation period, some help from the ovaries is essential. The corpus luteum starts releasing progesterone so the endometrium stays intact. If there is an issue with these hormones, it may be possible to rebalance with hormonal medication.

Endometrium Signs During Pregnancy

Sometimes the endometrium can give signals that pregnancy is happening. Light bleeding, such as brown discharge, a sort of egg-white mucus tinted brown, or even slight pinkish spotting can appear, indicating the embryo’s implantation in the endometrium. The embryo reaches the uterus after a journey through the tube and then begins to implant. This process is nidation, and means pregnancy itself has just begun! After this implantation, HCG hormone starts to be released and then slowly appears in the bloodstream and urine. This is the hormone detected by pregnancy tests.

Importance of the Endometrium in Pregnancy

When we say that pregnant women do not menstruate, it is because without the endometrium there is no way for the baby to survive in the early stages of pregnancy. It is what shelters and nourishes the baby until the placenta forms. The baby needs the endometrium—that is, what becomes menstrual blood is actually necessary for the pregnancy to progress healthily. Some doctors avoid prescribing any medication to maintain the endometrium in order to help nature expel any embryo that is unviable for growth. This is what we call natural selection.

In summary:

  • A good endometrium has: good thickness, is trilaminar, and secretory.
  • Endometrium suggestive of pregnancy: Between 8mm and 15mm.
  • Thin endometrium: does not have the capacity to hold the embryo.

The endometrium is necessary for pregnancy to occur. It complements ovulation, and we can say that the endometrium and pregnancy truly are a perfect match.

See also: First Pregnancy Symptoms