Transverse Lie

Transverse lie is a fetus whose long axis is at right angles to the long axis of the mother, found more often before 32 weeks than at term. Causes are multiparity with a lax uterus, polyhydramnios, placenta previa, uterine anomaly, fibroids, a contracted pelvis, prematurity and twin pregnancy. It matters because vaginal birth is impossible for a term baby, and labour or membrane rupture causes cord prolapse, obstructed labour and uterine rupture.

• Risk factors: grand multiparity, placenta previa, polyhydramnios, uterine fibroid or anomaly, pelvic tumour, twin pregnancy, prematurity.
• Most convert to longitudinal by 37 weeks, so persistent transverse lie at term is the concern.
• Planned admission and delivery prevent most complications.

Women have a wide abdomen with fundal height smaller than dates, a head felt on one side and the breech on the other, and an empty pelvis above the pubis. Most have no symptoms until labour starts.

• Wide uterus with the fetal heart heard below the umbilicus.
• Empty lower pole and a high presenting part.
• Differential diagnosis: oblique lie, unstable lie, breech presentation, twin pregnancy, placenta previa, uterine anomaly, fibroid.
• Complications: cord prolapse, shoulder presentation and obstructed labour, uterine rupture, arm prolapse, fetal death, caesarean section, postpartum haemorrhage, maternal death.

The diagnosis is made by abdominal palpation, confirmed by ultrasound.

• Abdominal examination: long axis across the uterus, head in a flank, nothing over the pelvic brim.
• Ultrasound: lie, placental site (to exclude previa), liquor volume, fetal anomaly, uterine anomaly, fibroids or adnexal mass, estimated fetal weight.
• Cardiotocography; blood group and haemoglobin.
• Repeat scan at 36 to 37 weeks to confirm persistence of the lie.

The principle is to exclude a cause, attempt external cephalic version at 36 to 37 weeks if it is safe, and plan caesarean section at 38 to 39 weeks, with admission at 37 weeks for women at risk of cord prolapse.

• Supportive: avoid vaginal examination until placenta previa is excluded; advise to attend at once for contractions, leaking fluid or bleeding; admit at 37 weeks if the woman is a grand multipara, lives far from the facility, or has polyhydramnios; two cannulae and group and cross-match in labour; knee chest position if the cord prolapses.
• Pharmacological: terbutaline 0.25 mg subcutaneous once, 15 minutes before external cephalic version; anti-D immunoglobulin 500 IU IM within 72 hours after version for RhD negative women; cefazolin 2 g IV as a single dose before caesarean section; betamethasone 12 mg IM twice, 24 hours apart, for delivery before 34 weeks and 6 days; oxytocin 10 IU IM after birth, then 20 IU in 1 litre Ringer's lactate at 125 mL per hour for 4 hours; tranexamic acid 1 g IV over 10 minutes if bleeding exceeds 500 mL.
• Procedures: external cephalic version at 36 to 37 weeks with cardiotocography before and after, in a theatre capable facility (contraindicated with placenta previa, bleeding in the last 7 days, abnormal cardiotocography, ruptured membranes, severe preeclampsia, a uterine scar in some units, and multiple pregnancy except the second twin); planned caesarean section at 38 to 39 weeks if the lie persists; emergency caesarean section for labour, rupture of membranes, cord prolapse or bleeding.
• Special groups: preterm transverse lie before 34 weeks is observed because most convert; twin pregnancy with the second twin transverse allows internal podalic version under general anaesthesia with glyceryl trinitrate 400 micrograms sublingual.
• Red flags: contractions, leaking fluid, bleeding, cord or arm in the vagina, reduced fetal movements, bandl ring.
• Follow-up: weekly review from 36 weeks; repeat scan at each visit for lie; newborn examination; counselling that the next birth should be in a facility.