Maternal serum markers of placental damage in uncomplicated dichorionic and monochorionic pregnancies in comparison with monochorionic pregnancies complicated by severe twin-to-twin transfusion syndrome and the response to fetoscopic laser ablation.

OBJECTIVE: Twin-to-twin transfusion syndrome (TTTS) is a morbid perinatal condition associated with abnormal placentation and is treated by fetoscopic laser ablation (FLA). We assessed basal maternal serum alphafetoprotein (MSAFP) and free beta-human chorionic gonadotrophin (f-betaHCG) in uncomplicated dichorionic (DC) and monochorionic (MC) twin pregnancies and a cohort of MC twin pregnancies complicated by severe TTTS. Changes in MSAFP and f-betaHCG post-FLA were measured as markers of placental coagulation. STUDY DESIGN: In a prospective case-cohort study, MC twins complicated by TTTS (n=23) were studied. A cohort of uncomplicated DC (n=12) and MC (n=6) twin pregnancies, which were appropriately grown for gestation with normal liquor volumes were also studied. Using solid phase, two site fluoroimmunometric assays, both MSAFP and f-betaHCG from uncomplicated and complicated cohorts were measured. Samples were taken, prior to FLA then at intervals after the procedures (6h, 24h and 1 week). RESULTS: The median multiples of median (MoM) were not significantly different in uncomplicated DC twin pregnancies for MSAFP 1.85 (95% CI 1.62-2.34) or fbetaHCG 1.66 (95% CI 1.21-2.04) compared to uncomplicated MC twin pregnancies (MSAFP 1.40 (95% CI 1.16-2.58) and fbetaHCG 1.70 (95% CI 0.32-3.35)). However, the median MSAFP MoM in MC twin pregnancies complicated by severe TTTS was increased (MSAFP 3.10 (95% CI 2.67-4.43); p<0.05) with a more significant increase being noted in median fbetaHCG (MoM 5.75 (95% CI 5.22-9.12); p<0.0001) compared to uncomplicated twin pregnancies. Post-FLA, the median MSAFP increased significantly at 6h by 445% (636.65 U/ml (95% CI 616-1216.9 U/ml)) and remained elevated at 1 week (553.4 U/ml (95% CI 203.7-3020.8 U/ml; p=0.001)). No significant difference in median fbetaHCG was noted post-FLA (p=0.36). This rise in MSAFP appears unrelated to the number of placental anastomoses coagulated or the total energy used. Also, in the small cohort in which amniodrainage alone was performed no rise in MSAFP was noted. CONCLUSIONS: MSAFP and fbetaHCG are increased in TTTS indicating an association with abnormal placentation. Post-FLA, a significant rise in MSAFP was noted for up to a week post-coagulation. This was not noted after amniodrainage.

Recurrence of fetal macrosomia in non-diabetic pregnancies.

Fetal macrosomia (birth weight >/=4,500 g) is known to increase a number of adverse maternal and perinatal outcomes. Although there is a clear association between maternal diabetes mellitus and fetal macrosomia, the majority of macrosomic infants are born to non-diabetic mothers. We wished to determine the recurrence rate of macrosomia in non-diabetic pregnancy and to see if a history of multiple prior macrosomic infants confers additional risk. A retrospective analysis of 14,461 term, singleton, infants born to non-diabetic mothers in 1997 and 1998 was performed, using a computerised hospital database. Among 14,461 term pregnancies, 529 infants (3.7%) were macrosomic, and the incidence was significantly higher in parous women (4.6%) compared with nulliparas (2.4%, p < 0.0001). Over the next 5 years, 164 of these women returned for another delivery. Women with a history of one macrosomic infant are at significantly increased risk of another macrosomic infant in a subsequent pregnancy (OR 15.8, 95% CI 11.45 - 21.91, p < 0.0001). For women with two or more macrosomic infants, the risk is even greater (OR 47.4, 95% CI 19.9 - 112.89, p < 0.0001). Macrosomia was associated with increased rates of instrumental delivery and anal sphincter injury regardless of parity, and additionally with increased rates of caesarean delivery and shoulder dystocia among nulliparas. Overall, 88% of women who laboured with a macrosomic infant achieved vaginal delivery.