Pregnancy of Unknown Location

Pregnancy of unknown location is confusing as well as emotionally painful. I break down what it means and how you have to manage it.
Pregnancy of Unknown Location
Miscarriage Pregnancy October 3, 2021
Pregnancy of unknown location is such a nightmare. It’s normal to wonder what the heck your doctors are talking about – “what do you MEAN you don’t know where the pregnancy is??” Early in pregnancy, a pregnancy may be too small to be seen on an ultrasound, so you’re given the diagnosis pregnancy of unknown location, or PUL. When doctors know you’re pregnant but can’t see it on ultrasound, they can monitor your pregnancy hormone levels (hCG) in your blood. These levels can indicate to your doctor if your pregnancy is growing (the levels are rising) or if the pregnancy is ending (the levels are falling)
hCG levels
Your hCG level is supposed to double every two days. But we have a minimum number that the hCG should rise by, and it depends on where the numbers are starting. For nerds like me who are interested in the precise numbers:
  • If your initial hCG level is less than 1,500 mIU/mL, it should rise at least 49% every two days.
  • If your initial hCG level is 1,500–3,000 mIU/mL, it should rise at least 40% every two days.
  • If your initial hCG level is greater than 3,000 mIU/mL, it should rise at least 33% every two days.
If your hCG levels don’t rise by this amount twice in a row, you know it’s not a normal pregnancy. It could either be a miscarriage inside the uterus (that’s too small to be seen by ultrasound), or it could be an ectopic pregnancy (likely in your fallopian tube).
PUL Management
Once doctors know that your pregnancy is not growing normally, there are two choices for management.
  • The first option is to perform a D&C to see if the doctors can detect any chorionic villi that would confirm it’s a pregnancy inside the uterus. If they saw villi, they would know it was an intrauterine pregnancy, and you wouldn’t need any more treatment. If they DIDN’T see villi, they would continue to monitor your hCG levels to see if they go down. Sometimes the pregnancy is so early, the pathologist can’t find villi even if the pregnancy actually was in the uterus. But if the levels don’t go down, the conclusion would be that the pregnancy was outside the uterus. The medical treatment for an extra-uterine pregnancy is methotrexate (MTX).
  • The second option is to skip the D&C drama and go right to methotrexate. Some patients who choose this end up “not needing it” (if the pregnancy was actually inside the uterus), but it’s the fastest way to start treatment for a pregnancy you know isn’t normal.

Without a D&C, doctors won’t know for certain if your pregnancy was inside the uterus or not. But once you know that the pregnancy isn’t normal, it’s okay to go ahead and start treatment. What IS normal after getting methotrexate is bleeding on and off for 6 freaking weeks. Why do you bleed so much, when your uterus looked “empty” and the pregnancy may have been stuck in your tube? The presence of pregnancy hormone in your blood causes your uterus to prepare for a pregnancy. The uterine lining starts to thicken – it’s like a padded satin pillow waiting for the jewel of the pregnancy. Even if that jewel never arrives, the thickened lining will need to shed. Hence, frequent bleeding and often cramping. It is important to keep monitoring your hCG levels until they reach <5 (or whatever your doctor considers zero), to be absolutely sure the pregnancy is over.

I know it doesn’t feel like it now, but your body is going to heal from all of this. And so will your heart. I recommend that my patients delay the next pregnancy for at LEAST 3 months (6 months is safer); since methotrexate is so damaging to pregnancy, we wouldn’t want you getting pregnant with MTX still in your system. It’s such a difficult journey, but you’re going to be okay.
Dr. Kate White / About Author
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