ECTOPIC PREGNANCY

Lost child

An ectopic pregnancy refers to when a fetus implants somewhere other than the uterus, most commonly in the ampulla of the fallopian tubes (95% of ectopics occur in the tubes). After implanting in foreign lands, the zygote begins to grow, crashing into the surrounding tissues. It can rupture delicate blood vessels, causing life-threatening bleeding if left to grow.

The biggest risk factor for an ectopic pregnancy is an architectural abnormality of the uterus and adnexa. Pelvic inflammatory disease (PID)  is one of the most common causes of adnexal scarring and distortion. Ectopics are also more common in older moms, smokers and with IVF. 

The patient, a sexually active premenopausal female, will present with unilateral lower abdominal pain often accompanied by vaginal bleeding. Their pregnancy test will be positive. Pregnancy tests work by measuring beta-hCG. So we know that this patient with abdominal pain is pregnant, but we don't know where the fetus has implanted. So let’s get an ultrasound and find out. Unfortunately ultrasounds are pretty fuzzy, and we can’t even see normal pregnancies until the b-hCG is over ~1,500. So there are three possible scenarios.

1. We see a fetus outside of the uterus. The diagnosis of ectopic pregnancy is easy to make!

2. We see a normal intrauterine pregnancy (IUP). We have ruled out ectopic pregnancy.

3. We don’t see any fetuses! It’s simply too soon to tell. So let’s track their b-hCGs. We can glean a lot of information from the b-hCG. The b-hCG doubles every 48 hours in a normal IUP. But in ectopic pregnancies, the b-hCG rises much slower. 

Ectopic pregnancies can be quite dangerous. Ectopics that are further along (b-hCG over 5,000) or have ruptured (shock, peritonitis, severe pain) are treated with surgery. Earlier cases can be treated medically with methotrexate. 

Uterine Rupture - if you’ve had a previous C-section, the surgical scar can burst during a later pregnancy. This is called a uterine rupture. It results in incredible abdominal pain with internal bleeding (hypotension) that is rapidly fatal. You can diagnose this on palpation, because when the uterus pops, the baby loses its amniotic fluid “shell” so you can very clearly feel fetal parts (arm or leg) when you touch the belly. For some reason, this condition causes bradycardia (and other arrhythmias) on the fetal heart monitor. 

Blueberry Muffin Baby - refers to a child covered in puerperal spots, resembling the blueberry chunks in a muffin. This is due to a persistence of something called extramedullary hematopoiesis, whereby normal fetuses make some RBCs outside the marrow, such as in the skin. Rubella keeps that process going through birth, resulting in clusters of hematopoiesis-related chaos in the skin. Although it’s classically associated with Rubella, it can be seen in most of the TORCH infections. It implies a more severe disease process. 

PERINATAL POTPOURRI

Baby bonanza

Sudden Infant Death Syndrome - newborns are sometimes found dead in their crib (3rd leading cause of death in this age group). There are no signs of trauma, and the autopsy is normal. We don’t know why SIDS happens, but we think that involves an immature neurological response to hypoxia. Evidence shows that sleeping prone, sleeping with blankets, sleeping outside the crib, second-hand smoke and prematurity are strongly associated with SIDS. 

Amniotic Fluid Embolism - rarely, a large amount of amniotic fluid makes its way into mom’s circulation, usually around the time of delivery. This has dramatic, often fatal, consequences. Although the presentation is variable, there are three complications that I would keep an eye out for: pulmonary emboli, shock and DIC. Consider it in any new mom who goes into an unexplainable shock. Treatment is supportive. There’s a great way to clinch the diagnosis, the bad news is that it’s an autopsy finding. Look for fetal cells inside of mom, particularly in the pulmonary vasculature. 

Postpartum Hemorrhage (PPH) - consider the four T’s

Tone - Uterine Atony (a floppy uterus) is the most common cause of PPH. Following a long labor, the mom has run out of oxytocin, so the uterus will be soft and boggy. Treat with a massage or Uterotonic medicines (see next page)

Trauma - there can be trauma to the uterus (Uterine Rupture), to the perineum (after an Episiotomy) or the the vagina itself (forceps)

Tissue - sometimes the placenta likes to stick to the uterus, and this is called Placenta Accreta. 

Thrombin - pregnant women are already slightly hypercoagulable, but other clotting disorders can precipitate PPH, such as Amniotic Fluid Embolism, DIC, sepsis, massive transfusion, etc.

Alpha Fetoprotein (AFP) is a lab marker in mom’s serum that helps to identify congenital disorders. It’s made in the fetus’s liver and gut

( ↑ ) Spina Bifida, Gastric Wall Openings (Omphalacele, Gastroschisis), Yolk sac tumor, Hepatocellular carcinoma

( ↓ ) Downs & Edwards syndromes. AFP is down in Downs.

Beta-hCG (human chorionic gonadotropin) is a molecule associated with pregnancy. It’s made by the placenta early on in the pregnancy, which is important for keeping the corpus luteum alive and well, so that it can pump out progesterone. The placenta simply isn’t ready yet. After a few weeks, the placenta reaches maturity, enabling it to take over the reins of hormone production from the corpus luteum. Once the placenta feels that it’s ready, it stops making b-hCG, causing the corpus luteum to wither away. Why does this matter? Well it explains morning sickness. b-hCG makes you incredibly nauseous. It peaks during the first trimester, which explains why morning sickness only occurs during that period! One other thing about b-hCG -- it’s what makes pregnancy tests turn positive. During the workup of a possible ectopic pregnancy, you trend the serum b-hCG, because normal IUPs double their b-hCG every 48 hours while ectopics do not rise as quickly. 

PREGNANCY DRUGS

Contraceptives

Copper IUD - kills sperm (hormone neutral). Most effective form of birth control. Also the most effective emergency option. Causes menorrhagia.  

Progesterone injection - thickens cervical mucus. Lasts for 3 months. Causes lots of weight gain. 

Progesterone IUD - thickens cervical mucus. Safe and effective. 

Progesterone implant - thickens cervical mucus. Safe and effective. 

Combination pill - negative hormonal feedback → no ovulation.

Ulipristal (Plan B) - progesterone blocker → makes uterine wall inhospitable to implantation

Abortion

Mifepristone - progesterone blocker → hostile uterus → fetus dies

Misoprostol - prostaglandin agonist → myometrial contraction (uterotonic) → expels fetal tissue (always used alongside Mifepristone)

Methotrexate - folic acid blocker (dihydrofolate reductase). Preferred agent in ectopic pregnancy 

Tocolytics

They slow contractions, giving the OB/GYN extra time to give steroids / transfer to a better facility

Nifedipine - CCB → less Ca++ flux → less smooth muscle contraction

Indomethacin - COX Inhibitor → less prostaglandins → less uterine contractions

Terbutaline - similar to albuterol (Beta-2 agonist) → ?? 

Uterotonics

They make the uterus contract, which may expedite delivery.

Oxytocin - made in the same place as ADH (posterior pituitary), so it’s a weak ADH analog and can cause SIADH

Ergometrine

Carboprost - PGF2 analog

Misoprostol - PGE2 analog

Antihypertensives

Nifedipine - CCB

Labetalol - beta blocker

Hydralazine - arterial relaxer, can cause lupus-like syndrome

Methyl-Dopa - alpha 2 agonist

Pain Relievers

Acetaminophen - only good option for pain

Antiepileptics

Magnesium - treats eclampsia