Teresa was 39 weeks and 4 days pregnant. The office nurse took her to an exam room to prepare for her prenatal visit with me. A few minutes later, the nurse poked her head into my office.
“She’s getting undressed so you can check her,” the nurse said. Since I was new to this practice, I hadn’t realized they routinely performed cervical exams from 37 weeks on. I went into the room and found Teresa sitting on the exam table, a flimsy paper sheet wrapped tightly around her. I introduced myself and asked her a few questions about her pregnancy, her family, and her desires for this birth. After listening to the baby’s heartbeat and measuring her belly, I told her she could get dressed and I would come back in so we could talk some. Her eyes widened: “Don’t you have to check me?”
I explained that checking her cervix would tell me nothing about when she would go into labor, and in fact, could increase her risk of infection during labor. Teresa assured me that she’d rather not be checked unless it was necessary; she had only complied with the nurse’s instructions because she thought she had to. We spent some time discussing her right to decline any procedure we suggested to her. Tersesa seemed appreciative of my approach, and we cordially said goodbye and planned a return appointment for the following week.
Heading back to my desk, I was again interrupted by the nurse. “Are you sure you want her to come back in a week? Didn’t you intend to schedule her for an induction?”
“An induction? Why?” I was suprised.
“She’s going to be 40 weeks and 3 days in one week!” the nurse exclaimed. She went on to tell me that, although the practice’s written policy recommended induction at 42 weeks, everyone in the practice encouraged women to submit to induction at 41 weeks.
“Is there evidence for inducing everyone by 41 weeks?” I asked. The nurse wasn’t certain, and I told her I’d prefer to wait until the next week to discuss induction with Teresa. Meanwhile, I went back to her chart and did some quick calculations.
At her first prenatal visit, Teresa had reported having periods every 45 days, not every 28, as the “due date” calculators are based on. What’s more, she had not had an ultrasound until she was 20 weeks pregnant, at which time an ultrasound can be as much as two weeks off on the dates. Since a woman normally ovulates 14 days BEFORE her next period starts, I calculated that Teresa had probably ovulated about the 31st day of her cycle. That would put her due date 17 days later than the one we had given her based on her last menstrual period. In fact, I noticed her due date based on her ultrasound was 9 days later than the one based on her last menstrual period, but her due date had not been changed because the rule of thumb for 20-week ultrasounds was that you don’t change the due date unless it’s greater than 10 days different than the date based on the last menstrual period. So here’s what Teresa’s numbers looked like:
Last menstrual period (LMP): April 15
Due date based on LMP: January 22
Due date based on a 45-day menstrual cycle: February 8
Here it was January 19, I was being prodded to schedule Teresa for an induction on January 29, because she would then be 41 weeks pregnant. Yet by my estimations, on January 29, she would only be 38 weeks and 5 days pregnant. In fact, if we waited until the last moment to induce her–42 weeks–she would still be three days shy of her due date based on her longer menstrual cycle!
Unfortunately, this is not an uncommon occurence. I have delivered numerous babies who were induced for being “overdue”, yet were born appearing very obviously NOT overdue. What’s happening here? Why are we so paranoid about going more than a few days past the due date?
In my next post, I’ll tell you the rest of Teresa’s story, and unpack the motives behind the push for inductions by 41 weeks.