Case 49: Pain in early pregnancy

 

Case 49: Pain in early pregnancy

CASE 49: PAIN IN EARLY PREGNANCY

History

A 39-year-old woman presents with left iliac fossa pain in pregnancy. The pain is intermittent 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.

Examination

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 tenderness on deep palpation in the left adnexa. On bimanual examination the uterus is

normal size and anteverted. There is some left adnexal tenderness but no obvious masses

are palpable.

INVESTIGATIONS

Transvaginal ultrasound findings are shown in Fig. 49.1.

Questions

• 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?

Figure 49.1 Transvaginal ultrasound scan showing a midsagittal view through the uterus.100 Cases in Obstetrics and Gynaecology

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ANSWER 49

Two distinct echolucent areas are visible within the endometrium. Each has a bright trophoblastic 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

• Gynaecological:

• corpus luteal cyst

• other non-pregnancy-related incidental ovarian cyst

• ovarian hyperstimulation (a rare complication of clomifene treatment)

• Non-gynaecological:

• constipation

• gastroenteritis

• urinary tract infection

• renal tract calculus

Ectopic pregnancy is effectively ruled out by the presence of an (twin) intrauterine pregnancy (heterotopic pregnancies occur in around 1 in 1000 women pregnant after ovulation

induction). Pelvic inflammatory disease is extremely uncommon in pregnancy as is irritable

bowel syndrome.

Further investigation

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 (suggestive

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 managed expectantly in pregnancy unless there is a suspicion of malignancy, torsion or symptoms are severe. Ovarian hyperstimulation is also easily

recognized on ultrasound scan. In this case the urinalysis is negative, there is no suggestive

history of a bowel problem and the adnexae appear normal; therefore reassurance should be

given and the patient discharged.

KEY POINTS

• Gynaecological and non-gynaecological problems are common causes of pain in

early pregnancy and should be investigated once an ectopic pregnancy has been

ruled out.

• Corpus luteal cyst is probably the commonest gynaecological cause of early pregnancy pain and is managed conservatively with analgesia and reassurance.