PAIN IN EARLY PREGNANCY
A 39-year-old woman presents with left iliac fossa pain in pregnancy. The pain is inter- mittent and cramping. She has had difficulty sleeping because of the pain, but has not taken any analgesia, as she is afraid that this may affect the baby. There is no vaginal bleeding.
The woman has a long history of secondary infertility. She had a spontaneous vaginal delivery at term 9 years ago, and started trying to conceive again soon after. She was investigated a year ago and found to have polycystic ovarian syndrome and was therefore commenced on clomifene citrate. This was her third cycle, her last menstrual period started 45 days ago and she had a positive pregnancy test 4 days ago.
The woman is apyrexial with normal blood pressure and heart rate. She is overweight (body mass index 32 kg/m2) and therefore examination is limited but there is some ten- derness on deep palpation in the left adnexa. On bimanual examination the uterus is nor- mal size and anteverted. There is some left adnexal tenderness but no obvious masses are palpable.
· What can you infer about the pregnancy from this ultrasound?
· What are the differential diagnoses for the pain?
· How would you further investigate and manage this patient?
Two distinct echolucent areas are visible within the endometrium. Each has a bright tro- phoblastic ring around confirming that these are gestation sacs. Neither sac demonstrates a definite yolk sac or fetal pole. The findings suggest a twin pregnancy with gestational age of 4–5 weeks, and this is consistent with the woman’s last menstrual period date. The sacs are distinct and therefore the pregnancy will definitely be dichorionic diamniotic. Zygosity cannot be determined by this ultrasound as both dizygotic pregnancy and a monozygotic embryo that split prior to implantation would give this appearance.
Differential diagnosis of pain in this woman is:
· corpus luteal cyst
· other non-pregnancy-related incidental ovarian cyst
· ovarian hyperstimulation (a rare complication of clomifene treatment)
· urinary tract infection
· renal tract calculus.
Ectopic pregnancy is ruled out as the ultrasound confirms an intrauterine pregnancy. Pelvic inflammatory disease is extremely uncommon in pregnancy as is irritable bowel syndrome.
The woman should be asked about constipation or loose stools, urinary frequency, dysuria or loin pain. Urinalysis for blood (suggestive of calculus) or nitrates/leucocytes (suggest- ive of infection) should be performed with midstream urine sent for microscopy, culture and sensitivity if positive.
The adnexae should normally be examined during the ultrasound examination. A corpus luteum is a very common cause of pain in early pregnancy and shows a typical peripheral blood flow pattern resembling a ‘ring of fire’ on colour Doppler examination. Corpora lutea resolve spontaneously by 12 weeks’ gestation.
Other ovarian cysts would also be easily seen on ultrasound – most can be safely man- aged expectantly in pregnancy unless there is a suspicion of malignancy, torsion or symp- toms are severe. Ovarian hyperstimulation is also easily recognized on ultrasound scan.
If the urinalysis is negative, there is no suggestive history of a bowel problem and the adnexae appear normal, then reassurance should be given and the patient discharged.