1. Premature Delivery Premature Rupture of Membrane Prolonged Pregnancy, Multiple Pregnancy Women Hospital, School of Medical, ZheJiang University Yang Xiao Fu

2. Preterm labour

3. Defined as delivery after gestation 28 completed weeks till 37 weeks (196-258 days). Birth weight 1000g - 2449g Preterm labour makes up 5% - 15% of total number of delivery Can the lower limit of preterm labour be brought earlier to 20 weeks gestation?

4. Diagnosis of preterm labour Labour occurring between gestation 28 completed weeks and 37 weeks regular uterine contraction: ≥ 4 times in 20 minutes or 8 times in 60 minutes cervical shortening of ≥ 75% progressive cervical dilatation of 2cm and above

5. Prediction of preterm labour Ultrasound assessing cervical length and internal os funnel formation, when internal os funnel is longer than the total cervical length by 25%, or total cervical length <3cm, indicating high possibility of preterm labour

7. Prediction of preterm labour Fetal fibronectine (fFN), after 20 weeks gestation fFN>50ng/ml, indicates possibility of preterm labour. Its sensitivity is up to 93%, specificity 82%

8. Premature rupture of membrane

9. Membrane rupture occurring before labour, known as premature rupture of membrane (PROM) Occurring after 37 completed weeks gestation, is called premature rupture of membrane at term Occurring before 37 weeks gestation, called preterm premature rupture of membrane (PPROM)

10. Effect to mother and fetus Feto-maternal infection Placenta abruptio Premature infant: 30% - 40% of premature labour is associated with premature rupture of membrane Cord prolapse, cord compression Poor fetal lung development and fetal compression syndrome

11. Post-term pregnancy Prolonged pregnancy

12. Gestation at or beyond 42 weeks gestation (>=294 days), known as post-term pregnancy Important factor for fetal distress, meconium aspiration syndrome, maturation disturbance syndrome, newborn asphysia, perinatal death, macrosomia and dystocia

13. Diagnosis Determine gestational age Calculation based on last menstrual period Calculation based on ovulation Ultrasound examination to ascertain gestation age Period of manifestation of early pregnancy symptoms, quickening First trimester pelvic examination assessing uterine size

14. Diagnosis Assess placental function Fetal movement count Fetal electronic monitoring Fetal biophysical profile ( Ultrasound) Urine E/C <10 or 24 hours urine E3 <10mg amnioscopy

15. Management Prevent post-term labour, effectively manage at term Decide appropriate mode of delivery based on integrated analysis of placental function, estimated fetal weight, cervical effacement, etc Induced labour Caesarean section Neonatal resuscitation

16. Multiple pregnancy

17. Conception of 2 or more fetuses in the same intra-uterine pregnancy Incidence of multiple pregnancy: 1:80 n-1 (n represents number of fetus in a single pregnancy)

18. Dizygotic twin Dizygotic twin makes up 70% of twin pregnancy Associated with ovulation induction, multi- embryo intrauterine transplantation and genetic factors Two separate ova being fertilized forming two zygotes, each genetic compositions is not identical, hence the differences in both fetuses

19. Dizygotic twin The placentas are usually dichorionic, can be fused together, but each has own independent blood circulation Two amniotic cavities are seen at the fetal surface of placenta, two layers of amniotic membrane and two layer of chorionic membrane present within

20. Monozygotic twin Monozygotic twin makes up approximately 30% of twin pregnancy Unclear cause, higher incidence in older pregnant women Single fertilized ovum differentiating into two fetuses, thus gender, blood type and other phenotypes are identical As the fertilized ovum differentiates at different times, forming 4 types

21. Diamniotic dichorionic monozygotic twin Differentiate within 72 hours of fertilization Form two independent fertilized ova and two amniotic sac, two layers of chorionic membranes and two layers amniotic membranes within the amniotic sacs Maybe single or two placentas Makes up approximately 30% of monozygotic twins

23. Diamniotic monochorionic monozygotic twin Differentiation occurs from 72 hours to 8 days of fertilization One layer of chorionic membranes and Two layers of amniotic membranes within two amniotic sacs Single placenta Makes up 68% of monozygotic twins

25. Monoamniotic monochorionic monozygotic twin Differentiation within 9-13 days after fertilization Both fetuses share a single amniotic cavity Single placenta Makes up 1% - 2% of monozygotic twins

26. Conjoined twin Differentiation after 13 days of fertilization, during which the primitive embryo has formed, the body cannot completely differentiate into two separate bodies, thus leading to different types of conjoined twins Incidence is 1/1500 of monozygotic twins

27. Conjoined twin