This post was written by Dr. Brian Radvansky and Michael Stephens.

It is with great pleasure and mild sorrow that we give to you the final installment of the Know Thy Shelf series, covering the much beloved OB/GYN shelf exam. No matter which facet of medicine you are interested in, OB/GYN is a fantastic rotation that will afford you a wide breadth of opportunities. You will scrub into the OR, interview women (and families) about sensitive health issues, and flex your patient education muscles on everything from STIs to the miracles of life. Then, of course, you will take a scintillating shelf exam to close things out.

The OB/GYN shelf is a comprehensive test of all matters related to obstetric and gynecologic medicine, and as a result, it covers a large breadth of material. 

High-Yield OB/GYN Shelf Exam Study Material

Here are decades of knowledge distilled down to a single blog post to get you through the test as smoothly as a fetus through the birth canal, along with a week-by-week OB/GYN Shelf study guide to get you through the six week study period.

A recurring theme: Know Knormal!

Because we are so pathologically focused, it can be difficult to accept things as normal. We are desperate to write a prescription for a medication when all it should say is “REASSURANCE q12 prn.”  

A lot of abnormal-sounding things are completely medically acceptable.

A new post-partum mother experiencing vaginal discharge after birth? As long as it’s not profuse bleeding, painful, or getting worse, call it lochia, and call it a day.

Is a newborn girl experiencing vaginal bleeding resembling menses? Don’t opt for child abuse screening, opt for normal withdrawal of maternal estrogen and progesterone and watch it subside with time.

A new mother is feeling upset, occasionally tearful, and not as thrilled as she expected to be 7 days after labor? As long as she doesn’t meet criteria for depression and isn’t a threat to herself or the baby’s livelihood, it is likely postpartum blues secondary to the labile swings in her hormonal milieu.

When your heart is beating at 150 bpm at rest, we worry, and at 60 bpm, we compliment you on your vagal tone. When the fetal heart is ticking away at 150 we are satisfied, and if it gets to 60 bpm, we are booking a spot in the OR.

The better you understand the foundational material, the more sense everything will make.

For instance, the physiologic changes of pregnancy are certainly testable, and will help you comprehend what is actually going on in the female body during pregnancy. Just about every system experiences some degree of change. By taking a systems-based approach to these changes, you’ll be sure to cover them all.

Some systems to remember as you prepare for your OB/GYN Shelf: 

• renal: increase in GFR with corollary decreases in BUN and creatinine 
• hormonal: increasing estrogen and progesterone
• weight gain: 25-35 lbs
• hematology: hypercoagulability (beware DVT/PE!) and dilutional drop in hematocrit
• cardiovascular: increases in cardiac output and blood volume with a decrease in blood pressure.

Expect the expected

Have upperclassmen told you that “there was way more GYN questions that I was expecting”?

Or maybe that the NBME gave them a test that was “almost completely OB”?

Take their recall bias with a grain of salt. The NBME will give you an even split down the middle of obstetric and gynecologic issues. That said, you should expect to see lots of common pathologies.

Make sure you have your different types of incontinence and vaginitis sorted out. Postpartum hemorrhage will almost certainly be on there (uterine atony until proven otherwise!).

Make sure you avoid your teratogens. Common ones to remember are drugs of abuse, ACE inhibitors, retinoic acids (check a b-hCG and recommend contraceptive if using isotretinoin), and anticonvulsants. And let us not forget the paragon of obstetric diagnoses: pre-eclampsia! Catch it early with good prenatal care, treat hypertension along the way, and use magnesium to avoid seizures.

One from column A, one from column B

A number of pathologies you will come across are quite similar to one another with small differences to set them apart. Know the hallmarks of each individual pathology to winnow it away from the rest. For instance, for your types of abortion: bleeding with closed cervix is threatened, bleeding with open cervix is inevitable, passage of some fetal tissue is incomplete, passage of all fetal tissue is complete, intrauterine death without passage of products is missed.

Another classic is placental pathologies. Shearing of the placenta from the wall, a placental abruption is characterized by both pain AND bleeding. Implantation of the placenta over the cervical os is a placenta previa (pre = before, via = the way; the placenta is in the way of the fetal escape) and is characterized by painLESS bleeding. Placenta accreta is the growth of the placenta into deeper layers of the myometrium.

Your 3 big vaginitis varieties are easily discernible. Motile organisms are trichomonas, cottage cheese discharge is candida, and clue cells with foul odor are Gardnerella, seen in bacterial vaginosis.

To wrap up, here are two final points to consider. Any woman of childbearing age with amenorrhea might be pregnant! Grab the low hanging fruit and start your “a woman has not had a period for 2 months” workups with a beta-hCG. It is simple, cheap, non-invasive, reliable, and can prevent you from doing an otherwise convoluted and esoteric workup. And finally, as in most cases, if you haven’t covered it before, it is probably not the right answer (i.e., don’t choose “sperm penetration assay”).

In addition to UWorld, NBME content outline and sample questions are helpful.

How to Study for the OB/GYN Shelf Exam

What is most important is to pace your studying to ensure your not cramming the days and weeks leading up to the exam. The following timeline will give you a play-by-play organized by week, along with what and how much you should be studying to maximize your success on test day; you can also find more information about the OB/GYN resources available to you.

The 6-Week OB/GYN Shelf Study Guide

Week 1

Diving into a new set of UWorld questions at the start of a rotation can be challenging; the result is often that you get many questions incorrect while you develop your foundation of knowledge for the given specialty.

This is perfectly fine; it is acceptable to be wrong on questions so long as you are learning the relevant concepts to get similar questions right come time for the real exam.

In other words, you should not feel compelled to “save” the UWorld for a later point in time once you have developed some proficiency with the subject.

Quite simply, the question bank is a learning tool and not a diagnostic one (i.e., it should not be used to extrapolate what score you might get on the real exam), so you should it for the purpose of learning the content–even if for the first time.

Furthermore, the longer you delay finishing the questions, the more likely you risk running out of time and having to race through what is arguably the most important resource to prepare for the exam. In short, for all of these reasons you should make sure to get a jumpstart on the UWorld as soon as possible upon beginning the rotation.

Week 2

As emphasized before, the UWorld is first and foremost among the resources to utilize and should be triaged accordingly. If you paced yourself well in the first week at about 30 questions a day, you should be able to have the bank finished by the end of the second week. In doing so, you’ll find that you will already have a great foundational fund of knowledge and sense of what is high-yield as you work through other resources.

It’s good to supplement questions with a textbook to balance out your studying. A number of options exist, each with different advantages; the important point is to pick one and stick with it.

Some recommendations include High-Yield Obstetrics and Gynecology and Case Files Obstetrics and Gynecology; a longer but very thorough option if you believe you will have the time to commit to it is Blueprints Obstetrics though you should be ready to finish about 20 to 25% of the textbook each week to keep up.

Weeks 3 and 4

In finishing the UWorld early, you will have freed up time to explore another question bank. Specifically for OB/GYN, the APGO set is particularly high-yield with a large volume of questions. The interface is different from the UWorld and divided into different objectives covering the breadth of the field.

Like the UWorld, you again should dive right in and focus on learning from the questions rather than using them to test yourself. A good strategy for these questions would be to complete about five objectives per day, which correlates to fifty questions so that you will be finished by the end of the fourth week.

During this time, you should also continue to work through the textbook you selected with a plan to be finished with about 75 to 80% of the book by the end of the fourth week.

Weeks 5 and 6

The advantage of this study plan is that by the last weeks of your rotation, you will have finished most of the highest-yield resources available and can use your remaining time to hone in on certain areas of weakness or review what you have learned a second time.

Specifically, given how well-written and researched the UWorld questions are, it is a great idea to go back through and repeat your incorrect questions.

Furthermore, if you recognize that there are certain topics you consistently find challenging, like fetal heart rate tracings or abnormal uterine bleeding, a great advantage of the APGO question bank is that the questions are divided into these different objectives; you may not have time to repeat the entire bank, but you should have plenty of time to go through your self-diagnosed areas of weakness.

Finally, you of course should finish off the textbook you have been working through.

If time allows, OnlineMedEd is an online short lecture series with videos covering most high-yield topics. This is a great resource to supplement your studies, though not as crucial as the questions. Especially in the last couple of weeks, this can serve as a nice rapid review as you lead up to exam day.

The bottom line

As with all exams covering clinically oriented medicine, the most important things are 1) to focus on questions and make these front and center in your preparation and 2) not to wait until the last minute to begin preparing! Following this schedule will help you hit both points and prepare you well for exam day success.

And that concludes the Know Thy Shelf series. You have done Socrates proud in your preparations. For, after one knows oneshelf, then and only then can he appreciate the universe’s esoteric concepts like medicine.