Fact Explanation
Identified during ultrasonography Multiple pregnancy, development of more than one fetus simultaneously in the uterus is commonly identified by first trimester dating ultrasound scan. Development of two fetuses, twin pregnancy is most common (1:80). Triplet, quadruplet pregnancies are rare.[1]
Excessive nausea and vomiting. The increased placental mass leads to excess production of beta-hCG.[2] Secretion of beta-hCG mainly occurs in the first 20 weeks peaking at about 12 weeks. During this period the patient may experience excessive vomiting which may progress to severe hyperemesis gravidarum.
Exaggerated symptoms of pregnancy The patient may experience excessive leg edema, worsening of varicose veins and hemorrhoids etc. Minor ailments such as heartburn, back pain, headache, urinary symptoms etc may also be exaggerated. The undue enlargement of the abdomen may cause cardio-respiratory embarrassment.[1]
Identified during the 2nd trimester by obstetric abdominal examination The abdominal examination may reveal large for dates pregnancy or multiple fetal parts.[1]
The patient may present with complications of multiple pregnancy later in pregnancy. Common complications that may arise are antepartum hemorrhage, hypertensive emergencies, preterm labor, preterm prelabor rupture of membranes etc. Patients may be detected with fetal issues such as discordant growth, intrauterine growth restriction, twin-twin transfusion syndrome, sudden fetal demise, vanishing twin etc.[3]
Etiological factors for multiple pregnancy Twin pregnancy is frequently seen among the black ethnicity. Increasing maternal age and family history of multiple pregnancy especially in the maternal side also increases the risk. Treatment modalities used for sub fertility such as ovarian induction and IVF is another factor increasing in incidence.[4]
  1. CHAUHAN SP, SCARDO JA, HAYES E, ABUHAMAD AZ, BERGHELLA V. Twins: prevalence, problems, and preterm births. Am J Obstet Gynecol [online] 2010 Oct, 203(4):305-15 [viewed 02 July 2014] Available from: doi:10.1016/j.ajog.2010.04.031
  2. HERSHMAN JM. Human chorionic gonadotropin and the thyroid: hyperemesis gravidarum and trophoblastic tumors. Thyroid [online] 1999 Jul, 9(7):653-7 [viewed 02 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/10447009
  3. RAO A, SAIRAM S, SHEHATA H. Obstetric complications of twin pregnancies. Best Pract Res Clin Obstet Gynaecol [online] 2004 Aug, 18(4):557-76 [viewed 02 July 2014] Available from: doi:10.1016/j.bpobgyn.2004.04.007
  4. CORCHIA C, MASTROIACOVO P, LANNI R, MANNAZZU R, CURRò V, FABRIS C. What proportion of multiple births are due to ovulation induction? A register-based study in Italy. Am J Public Health [online] 1996 Jun, 86(6):851-854 [viewed 02 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1380406


Fact Explanation
General examination : Pallor Multiple pregnancy may lead to anemia due to increased plasma volume and increased fetal iron requirements.[1]
General examination : Hypertension Multiple pregnancy is often associated with hypertensive disorders due to increased placental mass.[2]
Obstetric abdominal examination : increased symphysio-fundal height The presence of two fetuses will result in a larger fundal height than the gestational age
Obstetric abdominal examination : Two or more fetal poles Multiple fetal parts are felt on palpation. Finding of two fetal heads or three fetal poles confirm the diagnosis.
Obstetric abdominal examination : Two distinct fetal heart sounds In twin pregnancy two distinct fetal heart sounds will be heard at two different spots with an area of silence in between by two examiners. The two heart rates should have a difference of at least 10 beats.
  1. BEN MILED S, BIBI D, KHALFI N, BLIBECH R, GHARBI Y, CASTALLI R, KHROUF N. Iron stocks and risk of anemia in twins. Arch Inst Pasteur Tunis [online] 1989 Jul-Oct, 66(3-4):221-41 [viewed 02 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/2488539
  2. BDOLAH Y, LAM C, RAJAKUMAR A, SHIVALINGAPPA V, MUTTER W, SACHS BP, LIM KH, BDOLAH-ABRAM T, EPSTEIN FH, KARUMANCHI SA. Twin pregnancy and the risk of preeclampsia: bigger placenta or relative ischemia? Am J Obstet Gynecol [online] 2008 Apr, 198(4):428.e1-6 [viewed 02 July 2014] Available from: doi:10.1016/j.ajog.2007.10.783

Differential Diagnoses

Fact Explanation
Macrosomia Fetal macrosomia is defined as neonatal birth-weight over 4000g or more than 90% for gestational age. The cutoff levels need to be changed in accordance to sex and ethnicity. Risk factors for development of macrosomia include uncontrolled diabetes mellitus, maternal obesity, excessive maternal weight gain, prolonged pregnancy etc.[1] The symphysio-fundal height will be larger than for gestational age. Ultrasonic assessment during the antenatal period will reveal an increased estimated fetal weight.
Polyhydramnios Polyhydramnios is defined as increased volume of amniotic fluid above the 95th centile.[2] The aetiology could be idiopathic or secondary to failure of fetal swallowing (neurological, chromosomal anomalies), fetal gastrointestinal tract anomalies (duodenal atresia), fetal polyuria, congenital infection etc.[3] Polyhydramnios may cause maternal discomfort and respiratory difficulty. The fundal height is increased with a tense abdomen and impalpable fetal parts. Diagnosis can be made with an ultrasound scan.
Non-engaged fetal presenting part When the fetal presenting part fails to descend and engage in the pelvis the fundal height will be larger than the gestational age. Diagnosis can be confirmed by obstetric examination where more than two fifths of the fetal head is palpable abdominally.[4]
Inaccurate estimation of gestational age Comparisons between gestational age and fundal height might be erroneous if the gestational age is inaccurate.[4]
  1. CHAUHAN SP, GROBMAN WA, GHERMAN RA, CHAUHAN VB, CHANG G, MAGANN EF, HENDRIX NW. Suspicion and treatment of the macrosomic fetus: a review. Am J Obstet Gynecol [online] 2005 Aug, 193(2):332-46 [viewed 02 July 2014] Available from: doi:10.1016/j.ajog.2004.12.020
  2. CARDWELL MS. Polyhydramnios: a review. Obstet Gynecol Surv [online] 1987 Oct, 42(10):612-7 [viewed 02 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/3118281
  3. HAMZA A, HERR D, SOLOMAYER EF, MEYBERG-SOLOMAYER G. Polyhydramnios: Causes, Diagnosis and Therapy. Geburtshilfe Frauenheilkd [online] 2013 Dec, 73(12):1241-1246 [viewed 02 July 2014] Available from: doi:10.1055/s-0033-1360163
  4. NG SK, OLOG A, SPINKS AB, CAMERON CM, SEARLE J, MCCLURE RJ. Risk factors and obstetric complications of large for gestational age births with adjustments for community effects: results from a new cohort study BMC Public Health [online] :460 [viewed 19 September 2014] Available from: doi:10.1186/1471-2458-10-460

Investigations - for Diagnosis

Fact Explanation
Ultrasound scan (USS) A diagnosis of multiple pregnancy is confirmed by ultrasound scan. Determination the gestational age & chorionicity and screening for down syndrome should be done at the same US scan.[1]
Determination of chorionicity The most important aspect of ultrasonic assessment is to establish the chorionicity. Chorionicity should be determined by assessing the number of placental masses, lambda sign and ‘T sign’.[2] This is best performed in the first trimester when the accuracy of determination of chorionicity is high( close to 100%). The accuracy diminishes as the pregnancy progresses. Color flow doppler may be more useful in the third trimester.
  1. Multiple pregnancy: The management of twin and triplet pregnancies in the antenatal period. National institute for health and care excellence, September 2011 [Viewed on 29 June 2014]. Available from : http://www.nice.org.uk/guidance/cg129/chapter/introduction
  2. HASSAN T, O'COIGLIGH S, HIGGINS S. Prenatal diagnosis of chorionicity in twins. Ir Med J [online] 2011 Sep, 104(8):243-5 [viewed 02 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/22125879

Investigations - Screening/Staging

Fact Explanation
Anomaly scan A detailed anomaly scan should be performed to exclude congenital anomalies. Twin pregnancy is associated with a 4.9% increased risk of major congenital anomalies compared to singleton pregnancies.[1]
Nuchal translucency Ultrasonic assessment of the nuchal translucency at 10 to 14 weeks is a valid screening test that allows detection of chromosomal abnormalities and genetic syndromes.[1] A discordant nuchal translucency may be a feature of twin-twin transfusion syndrome.
Full blood count To monitor for development of anemia. Screen the patient at 20-24 weeks gestation and repeat at 28 weeks.[1]
Glucose tolerance test Women with multiple pregnancy have a higher risk of developing gestational diabetes.[2] Screen the patient at 24-28 weeks and monitor regularly.
  1. Multiple pregnancy: The management of twin and triplet pregnancies in the antenatal period. National institute for health and care excellence, September 2011 [Viewed on 29 June 2014]. Available from : http://www.nice.org.uk/guidance/cg129/chapter/introduction
  2. VIRJEE S, ROBINSON S, JOHNSTON DG. Screening for diabetes in pregnancy J R Soc Med [online] 2001 Oct, 94(10):502-509 [viewed 02 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1282202

Management - General Measures

Fact Explanation
Patient education and counseling The patient should be educated of the natural course of multiple pregnancy and the risks associated. Pregnant women with multiple pregnancy have an increased risk of facing pregnancy related complications compared to singleton pregnancies. Patients should be educated on the importance of regularly attending antenatal clinic visits. Patients with multiple pregnancy need more frequent clinic follow-up. The patient should be managed under a multi-disciplinary team including specialist obstetricians, midwives, ultrasonographers, an infant feeding specialist, dietician etc. Evidence is limited to support implementation of specialized ante-natal clinics for women with multiple pregnancy.[1] Discuss with the mother about the time and mode of delivery near term. The patient's wishes and expectations should be considered in the decision making process.
Dietary advice These pregnant women should be advised to maintain an adequate caloric intake to meet the increased need.[2]
Provide supplementary iron, folic acid and vitamins As preventive measures for development of anemia. Supplementation has shown to improve fetal growth. Further research is needed to support the use of specialized diets in multi-fetal pregnancies.[3]
Advise on adequate physical rest. Avoid heavy work. Adequate rest improves uteroplacental circulation and fetal growth. A policy of routine hospitalization for bed rest is currently not recommended until further evidence is acquired.[4]
  1. DODD JM, CROWTHER CA. Specialised antenatal clinics for women with a multiple pregnancy for improving maternal and infant outcomes. Cochrane Database of Systematic Reviews[online]. John Wiley & Sons, Ltd. 2012, 8 [viewed 02 July 2014]. Available from: doi:10.1002/14651858.CD005300.pub3
  2. GOODNIGHT W, NEWMAN R, SOCIETY OF MATERNAL-FETAL MEDICINE. Optimal nutrition for improved twin pregnancy outcome. Obstet Gynecol [online] 2009 Nov, 114(5):1121-34 [viewed 19 September 2014] Available from: doi:10.1097/AOG.0b013e3181bb14c8
  3. BALLARD CK et al. Nutritional advice for improving outcomes in multiple pregnancies. Cochrane Database of Systematic Reviews [online].John Wiley & Sons, Ltd. 2011, 6 [viewed 02 July 2014]. Available from: doi:10.1002/14651858.CD008867
  4. CROWTHER CA, HAN S. Hospitalisation and bed rest for multiple pregnancy. Cochrane Database of Systematic Reviews [online]. John Wiley & Sons, Ltd. 2010, 7 [viewed 02 July 2014]. Available from: doi:10.1002/14651858.CD000110.pub2

Management - Specific Treatments

Fact Explanation
Maternal complications Monitor the patients full blood count, blood pressure and blood glucose levels. Assess the haemoglobin level at 20-24 weeks to detect anemia and repeat at 28 weeks if necessary. Measure the blood pressure and test urine for proteinuria at each antenatal clinic visit. Patients with high risk factors for hypertensive disorders could be stated on aspirin 75mg from 12 weeks upto birth.[1]
Fetal complications Serial USS should be used for monitoring of fetal growth. Dichorionic pregnancies should be monitored 4 weekly from 24 weeks while monochorionic pregnancies 2 weekly from 18 weeks. Other common complications that should monitored for are prematurity, polyhydramnios, congenital malformations etc.[1]
Fetal complications : Monochorionic twins Twin-twin transfusion syndrome is the presence of aberrant placental anastomoses which result in hemodynamic imbalance between the two twins. The donor twin will develop oligohydramnios and IUGR while the recipient twin will develop polyhydramnios and hydrops. Diagnosis is made by ultrasonography. Treatment options include expectant management, laser treatment and selected feticide.[2] Other complications which are associated with monochorionic twins are umbilical cord accidents, conjoined twins, twin reversed arterial perfusion, acardiac twin etc.
Indications for referral to a tertiary level fetal medicine center The pregnant women should be referred for specialist opinion in the following situations : monochorionic monoamniotic twin pregnancies, monochorionic monoamniotic triplet pregnancies, triplet pregnancies and pregnancies with fetal complications. [1]
Timing of delivery Early delivery of multiple pregnancies have shown to be associated with less adverse outcomes while prolonging the pregnancy beyond certain gestations increases the risk of fetal death. Hence women with uncomplicated dichorionic pregnancies are offered elective birth from 37 weeks 0 days. Similarly women with uncomplicated monochorionic pregnancies are offered elective birth form 36 weeks 0 days while triplet pregnancies from 35 weeks 0 days. A course of antenatal corticosteroids is administered for attempted elective delivery prior to 37 weeks. Women who decline elective birth should be assessed weekly by ultrasound scan.[1]
Mode of delivery Vaginal delivery may be considered for dichorionic twin pregnancies where the first twin is cephalic. Elective caesarean section is indicated in monochorionic pregnancies, dichorionic pregnancies with first twin in a non-cephalic lie, in the presence of IUGR, congenital anomalies, higher order pregnancies, placenta previa, contracted pelvis etc.[3]
Preparation for labor Inform the relevant personnel beforehand and be prepared - senior obstetrician, anesthetist, neonatologist, midwife staff, theater staff. The patient should be provided adequate caloric supplementation with IV fluids. Blood should be cross matched and preserved. Pain relief is provided ideally with epidural anesthesia. Arrange facilities for continuous intrapartum fetal monitoring.[4]
Vaginal delivery of twin pregnancy The first twin is delivered as in normal labor and in certain instances outlet forceps may be required. Withhold IV ergometrine and cut the cord and deliver the first twin. Assess the presentation, lie and fetal heart sound of the second twin. A vaginal examination is performed to determine the status of the membranes and exclude cord prolapse. If the lie is longitudinal perform an amniotomy when the fetal presenting part is descending onto the pelvis. Oxytocin infusion can be used to augment uterine contractions. Vertex presentation is allowed to progress normally while the breech is delivered by assisted breech delivery or breech extraction. If the second twin is found to be in a transverse lie, external version is performed to convert the lie into longitudinal. Internal podalic version followed by breech extraction under general anesthesia is performed if external version fails.[5]
Caesarean section The main indication for caesarean section is the first twin being in a non-cephalic presentation. Emergency caesarean is required in fetal distress, cord prolapsed in first twin, non-progressive labor, locking of twins and placental abruption. Patients undergoing vaginal delivery should be kept nil by mouth in preparation for emergency caesarean section.[6]
Management of third stage of labor Multiple pregnancy increases the risk of postpartum hemorrhage due to uterine inertia. The over distended uterus may fail to contract adequately after delivery. The third stage should be managed actively with controlled cord traction, uterine massage and drug therapy. IV ergometrine is administered with delivery of the anterior shoulder of the second twin. An oxytocin infusion is started following delivery of the second twin.[4]
Preterm birth Women with multiple pregnancies have a higher risk of preterm birth compared to singleton pregnancies. A previous history of preterm birth with singleton pregnancy further increases the risk. The pregnant women should be informed of this risk. Fetal fibronectin and home uterine activity monitoring have poor predictive value for preterm birth. Cervical length measurement by TVS offers a better prediction.[7] Bed rest, cervical cerclage and oral tocolytics have shown no proven benefit up to yet and should be avoided. Corticosteroids should be administered if preterm labor is suspected.
  1. Multiple pregnancy: The management of twin and triplet pregnancies in the antenatal period. National institute for health and care excellence, September 2011 [Viewed on 29 June 2014]. Available from : http://www.nice.org.uk/guidance/cg129/chapter/introduction
  2. SOCIETY FOR MATERNAL-FETAL MEDICINE, SIMPSON LL. Twin-twin transfusion syndrome. Am J Obstet Gynecol [online] 2013 Jan, 208(1):3-18 [viewed 02 July 2014] Available from: doi:10.1016/j.ajog.2012.10.880
  3. Monochorionic Twin Pregnancy, Management (Green-top 51). Royal College of Obstetricians and Gynaecologists, 2008 [Viewed on 30 June 2014]. Available from : http://www.rcog.org.uk/womens-health/clinical-guidance/management-monochorionic-twin-pregnancy
  4. AYRES A, JOHNSON TR. Management of multiple pregnancy: labor and delivery. Obstet Gynecol Surv [online] 2005 Aug, 60(8):550-4 [viewed 25 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/16056013
  5. RABINOVICI J, BARKAI G, REICHMAN B, SERR DM, MASHIACH S. Internal podalic version with unruptured membranes for the second twin in transverse lie. Obstet Gynecol [online] 1988 Mar, 71(3 Pt 1):428-30 [viewed 02 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/3347429
  6. HOGLE KAREN L., HUTTON EILEEN K., MCBRIEN KERRY A., BARRETT JON F.R., HANNAH MARY E.. Cesarean delivery for twins: A systematic review and meta-analysis. American Journal of Obstetrics and Gynecology [online] 2003 January, 188(1):220-227 [viewed 02 July 2014] Available from: doi:10.1067/mob.2003.64
  7. CONDE-AGUDELO AGUSTíN, ROMERO ROBERTO, HASSAN SONIA S., YEO LAMI. Transvaginal sonographic cervical length for the prediction of spontaneous preterm birth in twin pregnancies: a systematic review and metaanalysis. American Journal of Obstetrics and Gynecology [online] 2010 August, 203(2):128.e1-128.e12 [viewed 02 July 2014] Available from: doi:10.1016/j.ajog.2010.02.064