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Premature Delivery Premature Rupture of Membrane Prolonged Pregnancy, Multiple Pregnancy. Women Hospital , School of Medical, ZheJiang University Yang Xiao Fu. Preterm labour. Preterm labour.
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Premature Delivery Premature Rupture of MembraneProlonged Pregnancy, Multiple Pregnancy Women Hospital , School of Medical, ZheJiang University Yang Xiao Fu
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% • progressivecervical 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 • 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 • 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