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Progesterone and pregnancy: a vital connection

Progesterone is a natural female hormone. Called “the pregnancy hormone,” it is essential before and during pregnancy.

Progesterone supplementation is often necessary during Assisted Reproductive Technology (ART) procedures, such as in-vitro fertilization (IVF) because the medications you may use during these procedures can suppress your body’s ability to produce progesterone. Certain procedures can even, inadvertently, remove progesterone-producing cells from your ovaries.

Sometimes, there are other reasons to use progesterone supplementation, such as little or no progesterone production from the ovaries or poorly developed follicles that do not secrete enough progesterone to develop the uterine lining.

The bottom line is this — all women who wish to become pregnant need progesterone to help the uterus prepare for and maintain a fertilized egg. Follow the links below to learn more about the connection between progesterone and pregnancy.

Before pregnancy

Progesterone prepares the uterus for pregnancy.  

After ovulation occurs, the ovaries start to produce progesterone needed by the uterus. Progesterone causes the uterine lining or endometrium to thicken. This helps prepare a supportive environment in your uterus for a fertilized egg.

 During pregnancy

Progesterone helps nurture the fetus.

A supply of progesterone to the endometrium continues to be important during pregnancy. Following a successful implantation, progesterone helps maintain a supportive environment for the developing fetus. After 8 to 10 weeks of pregnancy, the placenta takes over progesterone production from the ovaries and substantially increases progesterone production.


Forms of progesterone

Several types of progesterone are available, including vaginal products that deliver progesterone directly to the uterus. The different forms include the following:

Vaginal gel:

  • Used once a day for progesterone supplementation
  • Unique — the only once-daily FDA-approved progesterone for ART for up to 12 weeks of pregnancy
  • The only FDA-approved progesterone for replacement for donor egg recipients and frozen embryo transfers
  • Over a decade of experience and over 40 million doses prescribed
  • In studies where patient preference was measured, a majority of women preferred the gel for comfort and convenience over other progesterone formulations
  • Some discharge reported during use

Vaginal suppositories:

  • Compounded at specialty pharmacists
  • Wax-based
  • Widely used but not FDA-approved
  • Used 2 to 3 times a day
  • Leakage can be messy

Vaginal inserts:

  • Designed for vaginal use
  • FDA-approved for progesterone supplementation but not for progesterone replacement
  • Effective in women under 35 years; no established results in women over 35 years
  • Used 2 to 3 times a day

Progesterone oral capsules, used vaginally:

  • Not formulated or FDA-approved for vaginal use
  • Fewer side effects when capsules are used vaginally instead of orally
  • Used up to 3 times a day


  • An oil-based solution (sometimes called progesterone in oil)
  • Widely used; the oldest, most established method of progesterone delivery
  • Injected into the buttocks once a day
  • Require long, thick needle to penetrate layers of skin and fat
  • Difficult to administer by yourself
  • Injections may be painful
  • Skin reactions are common 

Choosing the progesterone supplementation for you

A decision that you and your health care provider can make together.

Progesterone is an important part of infertility treatment because it supports implantation and pregnancy. Health care providers often have a preference for which form of progesterone they prescribe for infertility treatment. Their preference is generally based on their experience with the various methods. But patient convenience and request are also important considerations.

Most women prefer a progesterone formulation that is easy, convenient, and comfortable.

So, be sure to discuss your options with your health care provider.

This section of the RESOLVE website is made possible in part by support from Church & Dwight Co., Inc., makers of First Response.