Although abnormal Pap smears are common in pregnancy, actual cancer is not. One out of every 1000 pregnant women will have a cancer. Pregnancy neither increases nor decreases the risk, but when cancer is diagnosed during a pregnancy, it presents a different management challenge. Now two lives are at stake.
The Importance of Pap Smears
In spite of its rarity, the most common cancer for a pregnant woman to get is cervical cancer, or cancer of the mouth of the womb. The fact that cervical cancer is the most frequent malignancy found during pregnancy underscores the importance of a Pap smear as a routine part of prenatal care. It is not only recommended during a pregnancy, but is considered mandatory.
If You Don’t Pass the Pap
This is one test you really do want to pass. But if the Pap smear does come back abnormal, don’t panic. Often, inflammation or hormonal changes may yield an abnormal but innocent Pap. The Pap smear is not a legitimate diagnostic test, but just a screen. When it’s abnormal, the obstetrician must make a real diagnosis by biopsy.
The good news is that, short of actual cancer, all of the pre-cancerous lesions of the cervix–called “dysplasia”–are easily followed with a conservative approach during the pregnancy.
That’s because dysplasias of the cervix are notoriously slow growing, allowing a lot of time for a patient to do other things–such as deliver her baby! Thereafter, follow-up with colposcopy (a microscopic exam) can determine if the lesion is worse or even still there. Many dysplasias simply fade away after a pregnancy.
So how dangerous to baby and woman is cervical dysplasia? The first thing one must do is arrive at a “real” diagnosis.
What Happens Next?
If there is a lesion, the obstetrician can trace it. Does it go up into the canal and out of sight, or can it be seen in its entirety? Cervical dysplasia and the progression to cancer is usually by continuous spread–it doesn’t jump around to the brain, lung, bone, etc., provided the lesion is surrounded by normal tissue. If a lesion is seen in its entirety under a colposcope (nothing more than a microscope on a stick), one can be pretty sure that there are no hidden surprises. When this is the case, periodic colposcopies are done throughout the pregnancy until management after delivery can be arranged.
What if the entire lesion cannot be seen, and observation through the colposcope demonstrates a lesion that seems to extend up the canal out of sight? This poses a particular problem and a risk, because no diagnosis is complete unless it is based on the complete lesion. If the only part seen is a very mild dysplasia, but nevertheless one that extends up the canal out of sight, it is invasive cancer. Managing it conservatively is a big mistake.
At this point, a cone biopsy is done. But, unlike a colposcopy, a cone biopsy is a big deal in pregnancy, because the doctor must whittle away at the cervix–that very structure holding the baby in the uterus. The depth of a cone biopsy will determine how weakened the cervix will become. Any weakening increases the risk of incompetent cervix and preterm labor and delivery.
There is a dividing line between the internal cervical cells and the external cervical cells. Since this “transformation zone” is the area where the internal cells are converted to external ones, this is where all of the action is. So if there’s a pre-cancerous lesion, this is the place it’s going to happen.
A cone biopsy usually must encompass this transformation zone to get a sample with “margins free” of cancerous cells. Luckily, in pregnancy the transformation zone is hormonally stimulated to be more external than internal, meaning that a shallower cone is possible to get the lesion. This is a break for the developing baby before term. But the later in the pregnancy the cone biopsy is done, the more risk of unreasonable bleeding and with it premature delivery.
This is why, if there is a problem, it is best that it be found as early in the pregnancy as possible. A pap smear should be part of the initial evaluation on every newly pregnant patient.
What Pregnancies Are Most at Risk?
Generally, a woman who has kept routine GYN appointments before becoming pregnant will not have a need for a cone biopsy, because progression to that point so quickly is unlikely if recent Paps have been normal. The woman who might need a cone biopsy in pregnancy is one who hasn’t had a Pap smear in several years. In her case, an abnormal Pap smear may represent a lesion that has had time to extend up the canal.
Cervical dysplasia is not a reason to terminate a pregnancy. Dysplasia is not cancer. And although all cervical cancers begin with dysplasia, not all dysplasias go on to become cancer. Only when there’s invasive cervical cancer does the ethical problem of termination come up. But this need not be a consideration for the pro-life patient when the invasion is “microinvasive” (less than 3 mm of invasion into the cervix) as long as it doesn’t get worse. There is a theoretical risk of spreading the disease by labor and vaginal delivery, indicating C-section as the mode of delivery. Abnormal Pap smears are common, and colposcopy will put the right perspective on things.
Because cervical cancer is a leading cause of death in women of childbearing age, it is something that can occur in the pregnant patient. With good routine care, however, pregnancy usually will be complicated only by pre-cancerous (dysplastic) lesions that require only a conservative approach that might be anything from just doing periodic colposcopy all the way to cone biopsy. But unless there’s invasive cervical cancer, the pregnancy should progress just fine–as should Mom!