What Is Recurrent Pregnancy Loss?

Recurrent pregnancy loss (RPL) is typically defined as two or more pregnancy losses, whether or not they occur consecutively. Traditionally, RPL referred only to clinical pregnancies confirmed by ultrasound, but many specialists now also consider biochemical pregnancies (very early pregnancy losses detected only by hormone testing).

How Common Is Recurrent Pregnancy Loss?

Pregnancy loss is more common than many people realize:

• 15–25% of all clinically recognized pregnancies end in miscarriage.
• Fewer than 5% of women experience two miscarriages.
• Only 1% experience three or more.

Age plays a major role:

• Age ≤35: first trimester miscarriage risk is typically 15% or lower.
• Age 40+: miscarriage risk can exceed 50%.

What Causes Pregnancy Loss and RPL?

There is no single cause of recurrent miscarriage. In many cases, RPL is linked to genetic abnormalities, but several other biological, hormonal, anatomical, and immunologic factors may contribute.

1. Chromosomal Abnormalities (Aneuploidy)

Most early miscarriages occur because the embryo has an abnormal number of chromosomes.

• Humans normally have 46 chromosomes (23 pairs).
• Errors during cell division can produce an embryo with an extra or missing chromosome.
• These conditions are known as aneuploidy and typically result in early miscarriage.
• Rarely, aneuploidy can result in a live birth (e.g., Down syndrome, caused by an extra chromosome 21).

Age-related risk: As female age increases, the chance of aneuploid embryos—and therefore miscarriages—increases. Aneuploidy is also a major reason infertility rises with age.

2. Uterine or Structural Abnormalities

Issues with the uterus can increase miscarriage risk, including:

• Fibroids
• Uterine scar tissue (adhesions)
• Congenital uterine anomalies (differences in uterine shape present from birth)

These conditions may affect implantation or growth of a pregnancy.

3. Hormonal and Endocrine Issues

Imbalances in thyroid hormones, prolactin, or other reproductive hormones may contribute to pregnancy loss. Treating the underlying hormonal disorder often improves pregnancy outcomes.

4. Blood Clotting and Immune Conditions

Certain autoimmune or clotting disorders—especially antiphospholipid syndrome (APS)—can increase miscarriage risk. APS is a well-documented, treatable cause of RPL.

5. Sperm Related Factors

While RPL is often approached from the woman’s medical history, sperm quality also plays a role. DNA fragmentation, oxidative stress, or other male-factor abnormalities may contribute.

How Is Recurrent Pregnancy Loss Evaluated?

A thorough evaluation looks at both partners and focuses on the most common factors associated with miscarriage.

Typical RPL testing includes:

• Genetic testing (possible parental karyotypes, review of prior pregnancy tissue if available)
• Hormone testing (thyroid, prolactin, ovarian function)
• Uterine imaging (ultrasound, saline sonogram, or hysteroscopy if needed)
• Antiphospholipid antibody testing
• Semen analysis and assessment of sperm health when appropriate

This comprehensive approach helps identify potential causes and guide individualized treatment.

How Is Recurrent Pregnancy Loss Treated?

Treatment depends entirely on what the evaluation uncovers—there is no single universal protocol.

Examples of targeted treatment include:

• Hormonal imbalances: medication to correct thyroid, prolactin, or luteal phase issues
• Antiphospholipid syndrome: blood thinners (e.g., aspirin or heparin) during pregnancy
• Uterine abnormalities: minimally invasive surgery to correct fibroids, adhesions, or structural anomalies
• Genetic causes: in vitro fertilization (IVF) with preimplantation genetic testing (PGT) may reduce miscarriage risk by selecting chromosomally normal embryos

What Is the Outlook for Patients With RPL?

The most encouraging fact is that most individuals with recurrent pregnancy loss ultimately achieve a healthy, successful pregnancy, even without major medical interventions. With proper evaluation, personalized treatment, and supportive care, outcomes are often very positive.