Cervical Incompetence

Another cause of miscarriage unrelated to chromosomal abnormalities in the embryo is frequently seen in women who have already had a child with a traumatic delivery, or who have had treatment for cancer of the cervix. It is called cervical incompetence. I will give an extreme example of a thirty-six-year-old couple who had been trying to have children for several years after the wife’s quite remarkable history of cancer. Several years before coming to see me, the wife had a Pap smear that identified an early cancer of the cervix that in the past would have been treated with hysterectomy. However, the woman knew she wanted to try to have a child, and she sought out a pioneer in cervical cancer in Toronto. This doctor performed a radical trachelectomy, removing only her cervix and saving the rest of her uterus. She still had her uterus, as well as a tiny opening from which she could menstruate and, hopefully, through which sperm could travel. But she was having a hard time getting pregnant.

Because of the rough Surface of this little opening to her uterus, which bled easily when she underwent IVF attempts in her local community, and despite the transfer of perfectly good embryos, she did not become pregnant. We did nothing differently in our IVF cycle other than transfer her embryos through a small abdominal incision (using ZIFT) into the fallopian tubes, rather than transvaginally via what remained of her scarred cervical opening. Thus, there was no uterine irritation caused by our embryo transfer, and as we anticipated, she became pregnant quite easily.

However, three months later, she began to go into early labor, and the opening into her uterus began to enlarge, simply because she had no cervix left. Her obstetricians were extremely quick and resourceful. They put her in an upside-down position, took her to the operating room, and performed cervical cerclage, tightly stitching the opening to the uterus. She then remained on bed rest and took drugs to prevent contractions (called tocolytic agents), and she wound up delivering a healthy baby girl many months later by C-section. What her case dramatically demonstrates is the importance of the cervix (the muscular passageway into the uterus) in acting as a sphincter to prevent premature delivery and miscarriage.

There are more subtle versions of cervical incompetence. A thirty-five-year-old couple from a very remote area of the world managed to make their way to St. Louis after eight years of infertility. The woman had become pregnant and delivered a healthy daughter twenty years earlier with a different partner. However, she was now unable to get pregnant. Her husband turned out to have a low sperm count, and she had severe adhesions on her fallopian tubes, preventing egg pickup from the ovary. So we performed IVF, obtained excellent embryos, transferred two of them, and froze the extras for future pregnancies.

However, at the time of embryo transfer, we warned her that her cervix looked as if it had been damaged from her previous traumatic delivery and that in fourteen weeks she would need to have a cerclage operation to cinch up her incompetent cervix tight, so as to hold the pregnancy. This couple was low on funds and did not fully believe what we had told them; they decided she would carry her pregnancy back in her remote home community. At eighteen weeks, her cervix opened up and she lost the baby. After traveling halfway across the world with undaunted dedication to her goal of having a baby, this woman’s perfectly normal pregnancy was lost because of a failure to stitch her previously damaged cervix at fourteen weeks.

The cervix can be damaged either by an aggressive Leep procedure to prevent cancer after a Pap smear comes back abnormal, or by the more unusual complete removal of the cervix because of cancer (trachelectomy). However, it can also be damaged by a traumatic, abrupt delivery, which, unbeknown to the patient, can lead to intrauterine scarring or to an incompetent cervix.

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