Premature Delivery Premature Rupture of MembraneProlonged Pregnancy, Multiple Pregnancy

Women Hospital , School of Medical, ZheJiang University

Yang Xiao Fu

Preterm labour

Preterm labour

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?

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

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

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%

Premature rupture of membrane

Premature rupture of membrane

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)

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

Post-term pregnancy

Prolonged pregnancy

Prolonged pregnancy

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

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

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

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

Multiple pregnancy

Multiple pregnancy

Conception of 2 or more fetuses in the same intra-uterine pregnancy

Incidence of multiple pregnancy: 1:80n-1

(n represents number of fetus in a single pregnancy)

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

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

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

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

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

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

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

Conjoined twin