Pap Smears in Pregnancy: necessary or not?

Last week, we talked about the Cascade of Interventions during labor.  This week starts a series about interventions during pregnancy that I believe could easily be seen as part of the dominoes set up before labor that can assist or at least pave the way to the cascade in labor.

Among the tests offered in pregnancy, a pap smear – a screening test to check for cervical cancer – may be one of the first.  If you’re seeing an OB, a pap smear is often offered at the first prenatal appointment.  

The current ACOG recommendation is to get the test once every three years between ages 21-65 with a few additional tests for the 30-65-year-old age group.  These recommendations hold true even if you’ve received the HPV vaccine (read into that what you want…).

Even with this as the current recommendation, we still see a large number of OBs not just suggesting but actually requiring a pap smear as part of their prenatal care.  It’s often offered in conjunction with testing for STIs.  While you can always decline any test or procedure, there’s the chance a doctor will choose to fire you as a patient for doing so.  

Why during pregnancy? What's the Rush?

As with any regular testing, the goal is early detection.  Regular pap smears have the goal of catching any changes in the cervical cells in order to prevent cervical cancer.  The challenge with a pap smear during pregnancy is that many things – simple irritation, infections, hormonal changes – can cause the test to come back as abnormal giving a false positive. 

While a practitioner may recommend a colposcopy (a more intense exam of the cervix) after an abnormal result, most will delay further biopsies or colposcopies until after the baby is born.  

About 5% (1 in 20) of women will have abnormal cervical cells from a pap smear, the majority of which prove to be non-cancerous.  However, up to 35% of women tested will have false negative readings – they have abnormal cells, but the tests come back clear.

If the abnormality is indeed a sign of cervical cancer, most practitioners will keep an eye on it but not worry as cervical cancer cells are very slow growing.  It typically does not progress during pregnancy as it takes about 10+ years for HPV to develop into cervical cancer.  

This begs the question – why are we performing this test during pregnancy if the results don’t change care?

Without going down the rabbit hole of if pap smears accomplish that goal and at what rate they do (refer to those stats above…), the biggest questions are what are the risks of performing this test during pregnancy, and what will the results change about how the rest of the pregnancy plays out?

Are there risks?

The risks of having a pap smear while pregnant are decently mild on the overall.

Most commonly, spotting or light bleeding is seen because the cervix is engorged and irritable.  

The more concerning risk is that of infection. Anytime a cervical exam of any kind is done, there is a chance of introducing infection.  During pregnancy, an infection has the possibility of impacting the amniotic fluid and baby. 

One hotly debated risk is miscarriage.  Anecdotal evidence points to there being some risk of miscarriage following a pap smear, but the medical establishment assures and reassures that there is no correlation or causation, and there is no risk to the growing baby.  

When done right, the test should only involve the very outer cells of the cervix so baby shouldn’t be disturbed.  Even so, one of the most commonly used tests, ThinPrep, states “do not use an endocervical brush during pregnancy” in their guide for use

While the risks tend to be mild, they are still important considerations before moving forward.

What changes in my pregnancy if the results are abnormal?

Depending on the practitioner, there are typically two courses of action if abnormal cells are found.  

The first is to retest after baby is delivered and proceed with care at that point based on the results of the retest.  The second is to restest every trimester to keep an eye on how the abnormal cells are progressing.  This option is typically reserved for cells deemed to have “high-grade dysplasia” which has a higher chance of turning cancerous.  

Because pregnancy can suppress the immune system, often these abnormal results will resolve themselves after birth.  The process of birth and shedding of cervical cells can also accomplish similar results as the procedures that burn or cut the pre-cancerous or cancerous cells out.

The Bottom Line

Especially if you have a history of regular results, delaying or declining the test during pregnancy is often acceptable by practitioners.  There is not much to be done during pregnancy regardless of normal or abnormal results.

The decision is ultimately in mama’s hands.