Fertility Q&A: Secondary Infertility, Birth Control Effects, Metabolic Health & More

Summary

Dr. Natalie Crawford and co-host Emily Whitlock answer four audience questions about fertility, treatment, metabolic health, and contraception.

1. Trying to Conceive After Previous Pregnancies

A year of trying to conceive without success warrants a complete fertility evaluation, even if someone has had children before. Previous pregnancies do not guarantee that the uterus, fallopian tubes, or sperm parameters are unchanged.

Key points:

• Letrozole may not improve the chance of pregnancy when someone already has regular cycles and no identified ovulation or luteal-phase problem.
• A full evaluation should include:
  • The uterus, with particular attention to the uterine cavity.
  • Whether the fallopian tubes are open.
  • A complete semen analysis, since sperm can change over time.
• For secondary infertility, clinicians may also consider conditions that can develop or become more relevant over time, including endometriosis, adenomyosis, and autoimmune disease.
• If the evaluation is normal and infertility remains unexplained, the episode describes two treatment approaches:
  • Ovulation induction monitored by ultrasound to produce two or more eggs, often combined with intrauterine insemination (IUI).
  • In vitro fertilization (IVF).
• The episode defines unexplained infertility as trying for a year with regular cycles, a normal semen analysis, a normal uterus, and open fallopian tubes.

2. Letrozole Timing

For people who do not ovulate regularly, starting letrozole on cycle days 3–7 or 5–9 is generally considered similar.

Timing may matter more when letrozole—or clomiphene—is used by someone who already ovulates and the goal is to encourage more than one egg to develop. Starting earlier may be preferred in that situation, because the body may already have begun developing a follicle later in the cycle.

3. Metabolic Health, Fertility, and Pregnancy Loss

The episode connects obesity, prediabetes, and high cholesterol with broader metabolic and inflammatory health. Dr. Crawford says obesity and prediabetes or insulin resistance are associated with lower chances of conception and higher miscarriage risk. She distinguishes cholesterol from these factors, noting that cholesterol is also needed for hormone production and pregnancy, and that its role is more nuanced.

Possible steps discussed include:

• Focusing on weight loss and improving metabolic health.
• Discussing options for insulin resistance, such as metformin or inositol.
• Considering a GLP-1 medication in the context of prediabetes.
• Discussing whether to pause attempts to conceive for a few months while addressing metabolic health.

The doctor emphasizes that repeated pregnancy loss can take a physical and emotional toll. She frames a temporary pause as something to consider with a clinician, not as a universal recommendation.

4. Birth Control and Planning for Pregnancy

Overall, studies do not show higher infertility rates among people who have used contraception compared with those who have not. However, different methods can affect ovulation, bleeding, and the timing of cycle recovery differently. Birth control may also conceal menstrual patterns or treat conditions that could matter for fertility.

Method-specific points and planning suggestions discussed:

• Depo-Provera injection: It can suppress ovulation for longer than the scheduled three-month interval in some people. The doctor recommends stopping it well in advance—up to two years before trying to conceive—to allow time for ovulation to return.
• Combined birth control pill: The hormones leave the body relatively quickly, and a “birth control cleanse” is not needed. The doctor recommends stopping the pill about 3–6 months before trying, mainly to observe cycle patterns and seek evaluation if they are irregular.
• Progestin IUD: It can alter the uterine lining. The episode notes that research has suggested changes in endometrial receptivity may persist after removal, particularly during the first six months. The doctor recommends removing it at least six months before trying, to allow time for the lining and menstrual pattern to recover.
• Long-term pill use: The doctor says long-term use has not been associated with lower pregnancy rates after stopping. It may also benefit some people by suppressing conditions such as endometriosis and reducing exposure to ovulatory cycles.

The overall message is not to fear contraception, but to plan its discontinuation based on the method and the reason it was started. If contraception was prescribed for a medical issue—or if periods are absent or irregular after stopping—it may be useful to investigate that before actively trying to conceive.

Other Content

The episode closes by thanking listeners for submitting questions and promoting Dr. Crawford’s book, The Fertility Formula, along with its preorder bonuses.

Speakers and Sources Featured

• Dr. Natalie Crawford — Host and fertility physician answering the questions.
• Emily Whitlock — Co-host, introduced as joining the episode.
• Audience question submitters — Anonymous listeners whose written questions are read aloud.
• Research studies — Referred to generally during the discussion; no individual studies or researchers are identified in the subtitles.