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
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