What Causes Recurrent Miscarriage?

Recurrent miscarriage defined as two or more consecutive losses is caused by chromosomal abnormalities in 50-80% of first-trimester cases and uterine structural defects in 15% and autoimmune disorders like antiphospholipid syndrome and hormonal imbalances including PCOS and thyroid dysfunction. Up to 50% of cases remain unexplained after full evaluation and maternal age above 40 significantly increases recurrence risk.

According to Dr. Hrishikesh Pai, renowned IVF Doctor in India, “Two losses in a row deserves investigation because finding the cause early often means it can be treated before the next attempt.”

Chromosomal problems in the embryo. That’s the big one at 50-80% of first-trimester losses. Uterine issues come next at about 15%. Then autoimmune problems and blood clotting disorders and hormonal conditions. And in roughly half the cases every test comes back normal and nobody can tell you why it happened.

• Chromosomal Abnormalities: 50-80% of first-trimester losses have abnormal chromosome numbers. Trisomy 16 is the most common at 26% of chromosomal losses. Then monosomy X and trisomy 22 and trisomy 21. About 5% of recurrent cases trace back to one parent carrying a balanced translocation that keeps producing unbalanced embryos
• Uterine Structural Defects: Septate uterus and bicornuate uterus and fibroids and polyps and intrauterine adhesions. All together they account for about 15% of recurrent losses. Good news is most of these get fixed surgically through fertility treatment before the next pregnancy
• Autoimmune Disorders: Antiphospholipid syndrome shows up in 15-20% of women with recurrent loss. What it does is form blood clots in the placental vessels which cuts off nutrients to the developing embryo. Aspirin plus heparin changes the outcome significantly for these patients
• Hormonal Imbalances: Uncontrolled thyroid dysfunction and PCOS push miscarriage risk up by 59% based on systematic review data. Poorly managed diabetes and elevated prolactin also play a role by disrupting how receptive the endometrium is to implantation

Only about 50% of recurrent miscarriage cases get a definitive answer after full workup. More about evaluation on the female infertility treatment page.

Depends on the cause. Chromosomal issues get IVF with PGT-A. Uterine problems get surgery. Autoimmune conditions get blood thinners. Hormonal problems get medication. And unexplained cases. Those still carry a 60-75% chance of successful next pregnancy with supportive care alone which surprises most people.

• IVF with PGT-A: Chromosomal problems causing repeated losses. That’s where IVF treatment with preimplantation genetic testing comes in. Only chromosomally normal embryos get transferred and that drops miscarriage rates from 30-40% down to under 10%
• Surgical Correction: Septum removal and fibroid excision and polyp removal and adhesion lysis. All done hysteroscopically as outpatient procedures. After surgery 60-80% of women conceive within 12 months which is a significant jump from pre-surgical rates
• Blood Thinner Therapy: Antiphospholipid syndrome patients get 81 mg aspirin daily plus heparin injections starting the day the pregnancy test turns positive. That combination takes live birth rates from 10-20% untreated all the way up to 70-80%
• Hormonal Management: TSH needs to be below 2.5 mIU/L before conception. PCOS gets metformin and progesterone support in early pregnancy. Diabetes requires HbA1c below 6.5% before trying again. Get the hormones right and the endometrium follows

Unexplained recurrent loss still has a favorable outlook with 60-75% achieving live birth next time around with close monitoring. What to expect after a loss is in this guide on heavy period after failed embryo transfer.

His team runs complete hormonal panels and imaging and tubal assessments before recommending any treatment. He has delivered keynote lectures at FIGO World Congress and been featured on BBC World Service for his work in egg freezing and reproductive medicine. Call +91-98200 57722 to book your consultation.

References

1. Genetic causes of recurrent miscarriage – Fertility and Sterility
2. Chromosomal abnormalities in recurrent miscarriage – National Library of Medicine