The Infertility Workup: History, Examination and Screening Tests

In a natural cycle, a cohort of follicles starts to grow under the influence of FSH, but only the most FSH-sensitive one becomes dominant and ovulates while the rest undergo atrophy. After ovulation, the corpus luteum releases progesterone, fertilization takes place in the fallopian tube, and around the fourth day the resulting embryo enters the uterine cavity and implants. Through the same cycle, estrogen from the growing follicle has been building up the endometrial lining in preparation. If pregnancy does not occur, that lining sheds, and that shedding is menstruation. Menstruation happens precisely because pregnancy has not occurred; if it has, the lining is not shed.

Ovarian reserve varies a great deal between individuals at the same age, so egg number is not always the limiting factor after 35 or 40; egg quality is. As age advances, errors in the meiotic spindle mechanism increase, making chromosomally abnormal eggs and embryos more likely, which raises both implantation failure and miscarriage risk: roughly 12 to 15% up to age 35, rising toward 20% between 35 and 38, 25% between 38 and 41, and around 50% after 42. For a woman who wants to use her own eggs, pre-implantation genetic testing can screen embryos before transfer, provided she has enough reserve to reach a day-five blastocyst. Endometrial receptivity also declines with age, independent of egg quality, which is why even donor-egg pregnancies become harder to sustain after 44. Ovarian rejuvenation therapy using platelet-rich plasma is being tried and shows promise for some women, though the evidence is still accumulating.

The procedure itself is not risky, but the implantation rate is only around 30 to 40%, which is why IVF success rates are not higher. Transferring more than one embryo to improve the pregnancy rate raises the chance of a multiple pregnancy, such as twins or triplets, well above the rate seen in natural conception. Placement technique also matters: pushing too much volume or placing an embryo too close to the fallopian tube raises the risk of an ectopic pregnancy, and in rare cases a heterotopic pregnancy can occur, where one embryo implants in the uterus and another develops in the tube, a complication seen almost exclusively with IVF.

A menopausal woman has no retrievable eggs of her own, but she can still conceive using a donor egg, which is a common and well-established approach even at a young age. After menopause the ovary is no longer producing estrogen, so hormones are given from outside to prepare the uterine lining, a donor egg is used, and the pregnancy proceeds and can be carried to delivery without issue.

It is used as a screening tool before starting any infertility treatment, whether ovulation induction, IUI or IVF, to know whether the woman carries an abnormal haemoglobin such as haemoglobin S or C, or is a thalassaemia carrier. If she is found to be a carrier, the male partner needs to be evaluated too, because of the inheritance risk: if both partners are thalassaemia minor carriers, for example, there is a 25% chance of a child being thalassaemia major. Couples in this situation may need genetic counselling or pre-implantation genetic testing, screening embryos for these conditions before transfer.

Age is the single most important prognostic factor for the success of any fertility treatment. Fertility is optimal between 20 and 30 years of age and declines progressively afterward, more steeply after 35.

Blood group typing and screening for sexually transmitted infections for both partners, and for the female partner, rubella and varicella immunity, a Pap smear or liquid-based cytology, haemoglobin electrophoresis, HbA1c, thyroid profile and vitamin D levels.