Progesterone in pregnancy and IVF: vaginal protocol, values, and FAQs

If you have just been prescribed progesterone in your fertility treatment, or you have had your levels checked during it, you arrive with legitimate questions: what we use it for, how it is taken, for how long, what to expect, and which numbers are considered normal.

Progesterone shows up at two different points in the journey: as support medication in some cycles (mainly in IVF, primarily ahead of the embryo transfer) and as a hormonal marker before transfer, both in IVF and during endometrial preparation. The two roles are managed differently, so it’s worth keeping them apart in your head.

In this guide we explain when we prescribe it, how the vaginal route works, which presentations are available (Progeffik, Utrogestan, Cyclogest, suppositories or pessaries depending on country), what side effects to expect, and which values are considered appropriate before the transfer. The exact protocol is always tailored by your medical team.

The role of progesterone in fertility treatment and pregnancy

Progesterone is the hormone that prepares the endometrium for implantation and sustains pregnancy in its first weeks. In a natural cycle it is produced by the corpus luteum of the ovary after ovulation, and from weeks 10-12 of pregnancy onwards the placenta takes over.

In assisted reproduction there are two key extras: ovarian stimulation and the egg retrieval (pick-up) itself alter how the corpus luteum works, so very often the ovary cannot produce enough progesterone on its own. That is why we prescribe pharmacological luteal support after retrieval. And in frozen embryo transfer cycles the ovary is suppressed, so progesterone is supplied entirely from outside.

If what you need is the diagnostic side (what a low number on a blood test means, what causes lie behind it, and which tests to request), we cover it in the full guide on low progesterone.

When we prescribe progesterone as medication

At Love Fertility Clinic, progesterone is part of the treatment protocol in four scenarios:

• After an IVF egg retrieval (luteal support). Follicular aspiration removes part of the granulosa cells that produce progesterone. We supplement it from the day after retrieval to sustain the endometrium while waiting for the beta-hCG result.
• In frozen embryo transfer (substituted cycle). We prepare the endometrium with estrogen first and add vaginal progesterone from 5 days before the transfer (the same goes for egg donation and other preparations without prior stimulation). Progesterone marks the implantation window: the day it starts determines synchrony with the embryo. In natural cycle preparations we also use it, although at a lower dose: in that case there is a corpus luteum still producing endogenous progesterone.
• In some intrauterine insemination (IUI) cycles. Not always prescribed; it depends on the protocol and the case.
• In confirmed pregnancy after treatment. Luteal support is maintained until the placenta produces enough on its own, typically between weeks 8 and 12 depending on the protocol and the pregnancy’s progress.

In consultation, we see it this way: progesterone is not an optional extra — it is a structural part of treatment when the ovary, because of the stimulation itself, cannot produce enough on its own.

Why vaginal progesterone is the most used route in assisted reproduction

In assisted reproduction the vaginal route is the standard one for a simple reason: it reaches the endometrium directly without going through the liver. That means higher local concentration and fewer systemic side effects (drowsiness, dizziness, fluid retention) than the oral route.

Reference protocols by route:

Deep intramuscular injection is rarely used today, because of discomfort and the availability of more comfortable alternatives. Dose and duration are set by your medical team based on the protocol and your individual response.

Micronized progesterone: Progeffik, Utrogestan, suppositories/pessaries and generics

In assisted reproduction the standard form is micronized progesterone: natural progesterone (the same molecule your body produces) processed into small particles that improve its absorption. It is not a “synthetic” version: it is the same hormone that circulates during the luteal phase and during pregnancy.

Commercially you’ll find it under several names. In Spain:

• Utrogestan
• Progeffik
• Seidigestan
• Cyclogest
• Generics under the international nonproprietary name (INN) “progesterone”

In the US these are most often called progesterone suppositories; in the UK and Ireland the term is progesterone pessaries. Same product, different name.

They are clinically interchangeable: same molecule, same standard doses. If a pharmacy switches your brand mid-treatment because of availability, that is not a problem, as long as the equivalent dose is maintained.

What you should not confuse: synthetic progestins (dydrogesterone, medroxyprogesterone, and others) are different molecules with different pharmacological properties. They are used in hormonal contraception, menopause hormone therapy, and a few specific fertility protocols. They cannot be swapped on your own with each other or with micronized progesterone. If a pharmacist offers you “something similar” because the prescribed brand isn’t in stock, check with us first.

How to use vaginal progesterone: protocol and application

Vaginal progesterone is applied in the form of soft ovules (vaginal capsules — known as suppositories in the US, pessaries in the UK) several times a day. The most common reference protocol in IVF is 200 mg every 8 hours (morning, afternoon, and night) or 400 mg every 12 hours (morning and night). Your team will tell you the exact protocol and the timing that fits your routine.

How to apply it, step by step:

• Wash your hands before handling the ovule.
• Lying down or reclined, insert the ovule into the vagina with your finger, as deep as you can.
• It is better to apply it before resting periods (at bedtime, or lying down for 10-15 minutes during the day): the horizontal position helps absorption and reduces how much comes back out as discharge.

The most frequent questions:

• What if I miss a dose? Apply it as soon as you remember, unless it is very close to the next one (in that case, wait and continue with the regular protocol). Do not double the dose to make up for it. If you have skipped several doses or the gap has been many hours, write to us before continuing.
• Is it normal for some of the ovule to come back out? Yes. Once dissolved, part of the oily excipient comes out as oily discharge, especially when you move or stand up. Progesterone has already been absorbed in good part, so do not repeat the dose unless the whole ovule comes out practically intact a few minutes after applying it.
• Can I have sex? Unless your team says otherwise, yes. The reasonable thing is to wait at least 1-2 hours between applying the ovule and intercourse.
• Can I exercise? Gentle, low-impact exercise is fine. Avoid very intense classes or strong impact right after applying the ovule: it increases how much comes out as discharge.
• What time of day is best? Doses are spread evenly across the day. If one application is at night, it’s best to do it right before going to bed.

If at any point the protocol raises doubts or the side effects are more than expected, write to us: we’d rather sort out a question early than leave you in the dark.

Side effects and what is normal

Vaginal micronized progesterone is usually well tolerated. The expected effects — none alarming on its own:

• Oily or whitish vaginal discharge: residue of the excipient, not infection.
• Increased breast tenderness (similar to premenstrual).
• Abdominal bloating or gas.
• Mild drowsiness, especially if some is absorbed systemically.
• Light vaginal spotting in the first few days: the application itself can mildly irritate the cervix.

When to write to us:

• Heavy bleeding (not light spotting), with or without pelvic pain.
• Intense or one-sided pelvic pain.
• Significant local reaction (burning, persistent itching, irritation that doesn’t ease).
• Any noticeable systemic effect that doesn’t fit your situation.

If you are on the oral route, drowsiness is more marked and the main dose is best taken at night.

Progesterone in the first trimester of pregnancy: what it does and how long it is maintained

If the beta-hCG is positive after a transfer, we keep up luteal support with vaginal progesterone during the first weeks of gestation. The reason: the corpus luteum (which keeps producing progesterone partly thanks to the beta-hCG secreted by the embryo) needs a handover until the placenta takes over full production.

That handover typically happens between weeks 8 and 12 of pregnancy. From that point the placenta produces enough progesterone on its own and pharmacological support can be withdrawn. The exact protocol (week of withdrawal, gradual tapering) is set by your team based on the protocol and the pregnancy’s progress.

Once pregnancy is confirmed and on track, we do not monitor progesterone levels via blood tests: clinical monitoring is done with serial beta-hCG and ultrasound scans. If you have doubts about your medication, write to us first before changing anything on your own.

If you want to dive into how to live the days between transfer and the beta, we cover it in the two-week wait guide.

Appropriate progesterone values before embryo transfer

In clinical practice we measure progesterone in the context of treatment, not during an already ongoing pregnancy. The values we actually look at are the ones before the transfer, because they signal whether the endometrium is ready:

• Follicular phase (before ovulation/retrieval and the start of exogenous progesterone administration): values should be below 1-1.5 ng/mL. A higher number at this point can indicate early luteinization and force us to reschedule the transfer.
• Early-mid luteal phase (before transfer): values should be above 8.8-10.5 ng/mL. That is the range we associate with an adequately primed endometrium.

These values are indicative and change with the laboratory and the unit used (ng/mL or nmol/L). Before comparing your result with numbers from Google, look at the reference range on your own report. The full reading is made by your medical team in the context of the cycle and the ultrasound scan.

Frequently asked questions about progesterone in pregnancy and IVF