Birth Control Causes Blood Clots, Right?
Not as much as having a baby . . .
A few years ago, I had a patient scheduled for repeat cesarean delivery. As the doctor on call, I took a few minutes to review her medical records before meeting her. Brianna’s* pregnancy had been uncomplicated. No high blood pressure or diabetes. Her first cesarean birth, three years prior, had also been uncomplicated with no excess bleeding or infection. In fact, there was only one significant thing in her medical history. When she was 19 years old, she had been diagnosed with a blood clot in her lungs . . . while she was taking birth control pills.
*not her real name
The electronic medical record told me that Brianna had been treated for her blood clot with many weeks of blood-thinning medication. She had tested negative for genetic (inherited) conditions that increase the risk of blood clots, and she had not had any other related problems afterward. Now in her mid-30s, her obstetrician had prescribed a once-daily blood thinner called enoxaparin for most of her pregnancy, then switched to a twice-daily blood thinner called heparin at 37 weeks of pregnancy in case she went into labor ahead of her scheduled cesarean. Seemed simple enough. I closed her chart and made my way to the pre-operative area.
I introduced myself to Briana and her partner, Dave** as the doc of the day who would be performing the cesarean. After the usual pleasantries, I asked if it was ok to confirm some items in her medical history.
“Any complications during this pregnancy?”
None.
“Any contractions, leaking fluid, or bleeding in the past 24 hours?”
No. Nothing.
They were expecting a boy. They wanted circumcision. Brianna hoped to breastfeed exclusively for the first few weeks and then supplement with formula.
“And when was the last time you took your heparin?”
“I didn’t.”
I assumed she had misunderstood me. “Well I know you didn’t take it today”, I chuckled awkwardly, “but when was the last time you took it?”
Brianna and Dave exchanged a look before she repeated herself. “I didn’t.”
“At all?” I could feel that my face was failing to hide my surprise.
“That’s right. I said I would, but then I didn’t. Is that a problem? Does it affect things today?” She was looking at her hands now, nervously twiddling her fingers.
“No . . .”, I spoke slowly and kept my tone even, trying to remember if I had just missed a note in the chart about Brianna declining the medication. “It does not affect things for the cesarean. But the risk of getting a blood clot is increased around pregnancy, especially in the six weeks after you give birth, and you have had blood clots in the past, so I do think it would be helpful to have a conversation with your OB about your plans for the next few weeks, especially with your history.”
“No I know, and I’ll definitely take it after. I just didn’t use it so far.”