Original Article
STUDY OF M ORPHOLOGICAL VARIATIONS OF 50 PLACENTAE W ITH
UM BILICAL CORDS AND ITS DEVELOPM ENTAL RELEVANCE
Asra Anjum *
1, D.Suseelamma
2, S.Saritha
3, T.V. Ramani
4, D.NagaJyothi
5.
ABSTRACT
Address for Correspondence: M rs. Asra Anjum, Lect urer of Anat omy, KAM S& RC, Hyderabad, Telangana, India. E M ail: asra.anjum1217@gmail.com
* 1 Lect urer of Anat omy, KAM S& RC, Hyderabad, Telangana, India.
2 Professor and Head, Dept of Anat omy, M amat ha M edical college, Khammam, Telangana, India 3 Professor and Head, Dept of Anat omy, KAM S& RC, Hyderabad, Telangana, India.
4 Asst Prof, Dept of Anat omy, KAM S& RC, Hyderabad, Telangana, India. 5 Asst Prof, Dept of Anat omy, KAM S& RC, Hyderabad, Telangana, India.
Introduction: The w ord “ Placent a” is a Lat in w ord and t he Greek equivalent w ord is “ Plakons” which m eans “ Flat cake on a plat e”. The placenta is a com plex m ult if unct ional organ. It provides nut r it ion, gas exchange, w ast e rem oval, endocrine funct ion and im m une support . Placent a is a special circulat ing syst em t o t he developing foet us. Being an organ of vit al im por t ance for cont inuat ion of pregnancy and foet al nut rit ion it has evolved great int erest am ong t he anat om ist s, em bryologist s, pat hologist s and obst et ricians.
M at erials and M ethods:The st udy w as done in 50 placent ae w hich w ere collect ed from t he depar t m ent of Obst et rics and Gynaecology in collaborat ion w it h t he depart m ent of Anat omy, Kam ineni Inst it ut e of M edical Sciences, Narket pally, Nalgonda, Telangana, during t he period of 2 years.The m or phological var iat ions of placent a, t he size, shape, w eight and at t achm ent of um bilical cord w it h it s blood vessels w ere obser ved, recorded and phot ographed. The prim e object ive of t he st udy is t o com pare and evaluat e t he m orphological alt erat ions of placenta and um bilical cord in pregnancy.
Results and Conclusion: In t he current st udy, t he m ajorit y of t he placentae show ed round shape, few placentae w it h oval and irr egular and w it h an accessory lobe in single placent a. The current st udy also includes variat ions in inser t ion of um bilical cords w as eccent ric in m ajor it y, cent ral, m arginal and velam ent ous in a few. Pregnancy induced hypert ension signif icant ly affect s t he placent a by r educing w eight and it does not have any significant eff ect on t he shape of placent a, um bilical cor d insert ion and num ber of cot yledons on m at ernal surf ace. The placent a is t he m ost accurat e r ecord of t he infant s prenat al experience.
KEY W ORDS: Placent a, Um bilical cord, m orphom et r y, variat ions, um bilical vessels.
INTRODUCTION
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Received: 12 Jun 2015 Accept ed: 30 Jul 2015 Peer Review : 12 Jun 2015 Published (O): 31 Aug 2015 Revised: 30 Jul 2015 Published (P): 30 Sep 2015
Int ernat ional Journal of Anat omy and Research ISSN 2321-4287
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DOI: 10.16965/ ijar.2015.198
The placent a is a com plex m ult if un ct ional organ of m ainly foet al origin w it h pleiot ropic r oles dur ing f oet al gr ow t h. It has a f oet al port ion for m ed by chor ionic f r ondosum of t r op h o bl ast d er i v ed f r o m t h e d evel o pi n g
embryo. The maternal portion formed by decidua basalis derived from t he modificat ion of ut erine lining of t he mother [1]. The placent a uses about 1/3rd of all t he oxygen and glucose supplied t o
The placent a is t he most accurat e record of t he infant s prenat al experience [3]. M at ernal sur-face is divided int o cot yledons w it h irregular gr o oves i n bet w een. The f o et al sur f ace is smoot h, shiny, t ranslucent and covered w it h amniot ic membrane [4].
The expelled placent a is a flat t ened discoidal m ass w it h an approximat ely circular or oval outline. It has an average volume of 500ml (range 200 – 950ml), an average w eight of 470gm s (r ange 200-800gm s), an aver age d iam et er of 185m m (r ange 150-200m m ), an aver age t hickness of 23mm (range 10 – 40mm), and an average surface area of c.30,000mm2. Thickest
at it s cent er and r api dly t hins t ow ar ds it s periphery where it continues as the chorion leave [5].
The placent a is usually regarded as a foet al o r gan . It is a v i t al o r gan f o r m ai nt ai ni n g p r egn an cy an d p r o m o t i ng n or m al f o et al development . It represent s t he co-operat ion of t w o dist inct individuals t o form single st ruct ure t hat prot ect s one and enables t he genes of t he ot her t o live on [6].
The umbilical cord connect s t he foet us w it h t he foet al surface of placent a. A fully developed um b ilical co r d i s app r oxi m at ely 1-2cm s in diamet er and average of 50-60cms long at full t erm . It s lengt h varies from 20-120cms. It is t ort uous causing false knot s. Normally umbilical co r d con t ain s t w o ar t er ies an d on e vei n surrounded by Whart on’s jelly, all enclosed in a layer of amnion. The cord deserves at t ent ion right from t he first t rimester. The umbilical cord normally insert s t o t he cent ral. Abnormalit ies in t he development , sit e of insert ion of umbilical cord and presence of single umbilical art ery can cause babies w it h cardiac and vascular defect s [7].
Present st udy has been undertaken t o record the d at a o n t h e m o r p h o lo gy o f pl acen t a an d umbilical cord and correlat e t he findings w it h review of lit erat ure.
M ATERIALS AND M ETHODS
of M edical Sciences, Narket pally, Nalgonda, Telangana, during t he period of 2 years.
The placent a w it h at t ached m em branes and umbilical cords w ere collect ed soon aft er t he del iver y. The placent ae w er e squ eezed t o evacuat e t he blood and w ashed under running t ap w at er. The m em branes w ere t r im m ed, labeled and t hen it w as fixed in 10% formalin. Examinat ions of t he placent ae w it h it s umbilical cords w ere carried out .
M orphological st udy of placenta w hich includes: size, shape, w eight and insert ion of umbilical cord. M orphological st udy of um bilical cord w hich includes: lengt h of cor d, num ber of vessels, coiling and knot t ed appearance.
OBSERVATIONS
The pr esent st udy included 50 placent ae of normal and abnormal pregnancies / foet uses.
The observat ion made during t he course of t he present st udy w it h relevance t o:
1) The shape of placent a, mode of umbilical cord at t achment and w eight of placent a.
2) The lengt h and number of blood vessels in t he umbilical cord.
Out of 50 placent ae st udied:
1) 39 placent ae w ere from normal pregnancies.
2) 5 pl acen t ae w er e f r o m hy p er t en si v e pregnancies.
3) 2 placent ae of mult iple pregnancies
4) 1 placent a of Acardia/ Acephalus or Trap sequence (Fig:10.a, 10.b)
5) 1 placenta of Omphalocele (Fig: 12)
6) 1 placenta of Sirenomelia (Fig: 11.a, 11.b)
7) 1 placenta of Anencephaly (Fig: 13)
A. 39 Placentae of Normal Pregnancies:
I . Th e w e igh t of t he p lace n t a in n o rm a l pregnancies varied from 400gms to 650gms.
1) 14 placent ae w eighs below 500gms
2) 22 placent ae w eigh bet w een 500-600gms.
3) 3 placentae w eighs more t han 600gms(Fig:6)
II. The shapes of the normal placentae studied w ere:
1) 30 placentae w ere round in shape. (Fig: 1)
2) 8 placentae w ere oval in shape (Fig: 12) The st udy is prospect ive, observat ional and
3) 1 placenta show ed accessory lobe (Fig: 5)
III. Insertion of umbilical cord:
1) 21placent ae show ing eccent ric insert ion (Fig:2)
2) 14 placentae show ing cent ral insert ion (Fig:1)
3) 3 placentae show ing marginal insert ion(Fig:3)
4) 1 placenta show ing Velament ous insert ion (Fig: 4)
B. 5 Placentae of Hypertensive Pregnancies:
I.The w eight of the placentae in:
1) 2 placent ae w eighs bet w een 300-400gm s (Fig: 7)
2) 3 placent ae w eighs bet w een 400-500gms
II.the shape of the placentae: 1) 2 placent ae w ere round in shape. 2) 3 placent ae w ere oval in shape III. Attachment of umbilical cord: 1) Eccent rical insert ion in 4 placent ae. 2) Cent ral insert ion in 1 placent a. C. Placentae in M ultiple Pregnancies:
Out of t w o mult iple pregnancies, one is a t w in and ot her is t riplet . (Fig: 8,9)
I.The w eight of the placenta in: 1) Tw in pregnancy 530gms (Fig: 8) 2)Triplet pregnancy 490gms (Fig: 9) II.The shape of the placenta in:
1) Tw in pregnancy – quadrangular (Fig: 8) 2) Triplet pregnancy – round (Fig: 9)
III.The place of attachment of umbilical cord in:
1) Tw in pregnancy – marginal (Fig: 8) 2) Triplet pregnancy – cent ral (Fig: 9) Umbilical Cord in Normal Pregnancies: Out of 39 umbilical cords st udied from normal pregnancies:
1) 2 umbilical cords w ere bet w een 30-40cms 2) 37 umbilical cords w ere bet w een 40-60cms Al l t h e 39 u m b il i cal cor d s f r o m n o r m al pregnancies show ed 2 umbilical art eries and 1 umbilical vein.
Umbilical Cord in Hypertensive Pregnancies: Out o f 5 um b i li cal co r d s st u d ied f r o m hypert ensive pregnancies:
1) 1 umbilical cord w as bet w een 30-40cms 2) 4 umbilical cords w ere bet w een 40-60cms Umbilical Cord in M ultiple Pregnancies: 1) In t w in and t riplet pregnancies t he umbilical cords lengt h w as less t han 40cms.
Abnormal Foetuses:
M orphological Variations of Placent a and Umbilical Cord in Omphalocele Foetus: Placent a: oval placent a show ing eccent r ic at t achment of umbilical cord, w eighing 500gms w i t h r et r o p lacent al h aem o r r hage o n t h e maternal surface. (Fig: 12)
Um bilical cord: um bilical cord is at t ached t o membranes of t he Omphalocele of t he foet us. Lengt h of t he cord w as 46cms w it h 2 umbilical arteries and 1 umbilical vein. (Fig: 12)
M orphological Variations of Placent a and Umbilical Cord in Sirenomelia Foetus:
Placenta: placent a show ing irregular shape wit h cent rally at t ached um bilical cord, w eighing 430gms. (Fig: 11.a)
Umbilical cord: lengt h of t he cord w as 40cms w it h single umbilical artery and single umbilical vein. (Fig: 11.b)
M orphological Variations of Placent a and Um bilical Cord in Acardia/ Acephalus (Trap Sequence- Tw in Reversed Arterial Perfusion): Placenta: Round placent a showing t wo umbilical cords w it h art erio-art erial and veno-venous anast omosis, w eighing 500gms. (Fig: 10.a) Um bi lical co rd: Tw o Um b i lical co rds w ere present . The t w in A (normal) cord w as long and edemat ous, t w in B had a short cord and bot h sharing t he sam e Placent a. Um bilical Cords show ing 2 um bilical art eries and 1 um bilical vein. (Fig: 10.a)
The umbilical art eries of t w in A anast omosis w it h umbilical art eries of t w in B. t w in B receives deoxygenat ed blood via t he umbilical art eries of t he t w in A. Umbilical vein of t w in B leaves and anast omosis w it h umbilical vein of t w in A. Umbilical vessels of t w in B are not connect ed t o t he placent al villi, on t he ot her hand t hey are connect ed t o t he umbilical vessels of t he t w in A, w hich is clearly seen on t he foet al surface of t he placenta. (Fig: 10.a, 10.b)
M orphological Variations of Placent a and U m bilical Cord in Anencephaly Foetus (20 Weeks):
Pla cen t a: Rou n d pl acent a w i t h cen t r al l y at t ached um bilical cor d w eighing less t han 100gms. (fig: 13.a)
Photographs of the placenta and the umbilical cord and its attachment:
Fig. 1: Placenta show ing round w it h
cent rally at t ached um bilical cord.
Fig. 2: Placenta show ing eccent ric
at t achm ent of um bilical cord.
Fig. 3: Placenta show ing m arginal
insert ion (Bat t ledor e Placent a).
Fig. 4: Placent a show ing velam ent ous
at t achm ent of um bilical cord.
Fig. 5: Pl acen t a sho w i ng
accessory lobe
Fig. 6: Placent a sh o w in g m o r e
w eight (650 gm s).
Fig. 7: Hypert ensive Placent a
show ing oval shape w it h less w eight (300 gm s)
Fig. 8: Placenta of t w ins show ing
quadrangular shape w it h 2 um bili-cal cords at t ached t o t he m argins.
Fig. 9: Placent a of t r i plet pregnancy
show ing round shape w it h 3 um bilical cords at tached t o t he cent er.
M orphological variations of placenta and umbilical cord in M alformation foetuses
Fig. 10a: Placenta and um bilical cord in Trap
sequence
Fig. 10b: Diagram m at ic representat ion of Art erio-art er ial
and veno-venous anast om osis in Acardia/ Acephalus t w ins.
Fig. 11a: Sho w ing siren om eli a fo et al placent a w it h
irr egular shape and cent rally at t ached um bilical cord.
Fig. 11b: Um bilical cord of sirenom elia case show ing
Fig. 12: Om phalocele foet us show ing oval placenta
w it h eccent r ic at t achm ent of um bilical cord. Fig. 13: Placenta and um bi lical cord in anencephaly.
DISCUSSION
Placent al grow t h occurs t ill 37t h w eek. In early
part of pregnancy about 800 t o 1000 st em villi radiate from t he ent ire chorionic wall. Later, w it h t he regression of chorion leave only 60 st em villi persist in human placent a. M at ernal cot yledons are 15 t o 30 and each cot yledon receives 2 t o 3 st em villi [8].
The foet al grow t h capacit y is det ermined by placent al w eight . Placent al w eight and foet al w eight w ill increase proport ionately, w it h t he progress of pregnancy [9].
Placent a responds t o exogenous insults and tries t o adapt f or var ying nut rit ional level of t he m ot her. If t his response of placent a fails t o maint ain foet al grow t h, t hen it result s in Int ra Ut erine Grow t h Ret arded babies or various congenit al defect s [10].
The placent a t herefore serves as t he major link bet w een a mot her and her unborn baby, t he foet us. Ow ing t o t he delicat e and im port ant nat ure of t he placent a it is somet imes referred t o as t he “ mirror of t he perinat al period [11]. The placent a has been described as t he mirror o f m at er n al and f oet al st at u s an d i t s morphomet ric changes reflect s due t o maternal hypert ension or diabet es and lead t o IUGR or foet al malformat ions.
Gunapriya Raghunat h, et al (2011) st udied 101 placent a and found t he average w eight of t he placent a 528.55gms in normal pregnancies and 398gms in hypert ensive pregnancies, shape of placent a in majorit y of cases is round (93%) and oval (7%) but no accessory lobe w as found. The average t hickness of t he placent a w as 2.1cms. The average number of cot yledons on mat ernal surface w as 18. According t o t hem 75.45% t he
insert ion of um bilical cord on t he placent a is cent ral or eccent ric, w hich w as considered w as norm al, 16.36% w ere m arginal, 7.27% w ere furcat e and 0.90% w ere velament ous insert ion [12].
The study done by Peter Kwabena Appiah (2009) in 265 placent a show ed t he average w eight of t he placent a as 563.47gms ± 132, t he average diamet er of t he placent a w as 18.69cms ± 2.05. Th e av er age t h ickn ess of t he p lacent a as 2.68cms ± 0.55. In his st udy, he found t he site of insert ion of um bilical cord on placent a is eccent ric in 21.14%, cent ral in 60.75% and marginal in 18.11% [13].
By t he fourt h gest ational week, 3 pairs of vessels are connect ed t o sinus venosus of foet al heart . By t he sixt h w eek, a crit ical anast omosis occurs bet w een t he left umbilical vein and t he hepat ic sinusoids. At t he same t ime, t he right umbilical vein involut es. Failure of t his norm al process result s in t he ext rem ely r ar e sit uat ion of a persist ent right um bilical vein. Persist ence of t he right um bilical vein result s in a 4 vessel umbilical cord (2 veins and 2 art eries) Prenat al so no gr ap h i c o b ser v at i o n o f m u l t i v essel um bilical cord is comm only seen in conjoint t w ins b ut also som et im es seen in healt hy neonat e w it hout any congenit al abnormalit ies. A 4 t o 6 vessel cord has been previously reported w it h conjoined t w ins [17].
Several combinat ions of vessels can give t he appearance of 4 vessel cords. It can be 2 veins and 2 art eries or one vein and 3 art eries. Four vessels cord result from t he persist ence of t he right umbilical vein i.e. 2 art eries and 2 veins. Some report s suggest an increase in congenit al anomalies (such as ect opia cordis, at rial sept al defect , sym m et r ical bifid liver, cleft lip and palat e, art eriovenous fist ulas of t he placent a) w hile ot hers do not [18].
In case of one vein and 3 art eries w hich is anot her common cause (5%), t he fourt h vessel is t he persist ence of sm all vit elline art eries. These rarely exceed 0.5mm in diameter. These ext ra vessels follow t he normal t w ist ing of t he m ain um bili cal ar t er ies. So t hat t he cor ds cont ain 3 art eries (4 vessel cord) or 4 art eries (5 vessel cord). These vessels run for t he w hole lengt h of t he cord and no congenit al anomaly w as observed [19]. The umbilical cord lengt h
normally varies from 24 t o 124 cm. In M aximum cases t he umbilical cord lengt h bet w een 51 and 60cms. Cord lengt h did not vary according t o t he w eight , lengt h, and sex of t he baby. The incidence of all t ypes of cord complicat ions w as associat ed w it h int raut erine problem . As t he number of loops in a nuchal cord (cord around t he neck) increases t o more t han t w o loops, it is t he indicat ion for operat ive procedure. The incidence of birt h asphyxia, cord ent anglement or cord prolapse w as significant ly more in long cords (>100cms) and placent al abrupt ion in short cor ds (<25cm s) as com pared t o cords w it h normal cord lengt h [20].
t o t he normal foet al grow t h.
Um bilical cord connect s t he foet us w it h t he mot her. It forms on t he vent ral body wall of t he f o et us bet w een t he per icar dial bul ge and ext ernal genit alia. Except ionally short or long cords are associat ed w it h foet al problems and com plicat ion during labor. The cord usually at t aches midw ay bet w een t he cent er and t he m ar gin of t he placent a. The um bilical cor d insert ion t o t he placent a show s num ber of variat ions. It can be cent ral, eccent ric, marginal or velam ent ous insert ion.An ext rem ely long cord may encircle t he neck of t he foet us usually w it hout increase risk w here as a short one may cause diff icult ies dur ing delivery by pulling placent a from it s at t achment in t he uterus [5,7].
The lean um bilical cords w er e obser ved in hypert ensive pregnancy by ult ra sonographic st udy. But no significant changes have been observed in umbilical cord dimensions [9].
Peter Kwabena Appiah during his st udy, he found the occurrence of 2, 3, 4 vessel cords w ere 1.13%, 95.85% and 2.64% respect ively, indicat ing t hat t he large majorit y of cords has 3 umbilical cord vessels (2 art eries and 1 vein) and 0.38% showed single umbilical art ery [13].
Sinan Karadeniz et al. st udied 259 placent ae and umbilical cords, in most of t he cases, t here w ere t w o umbilical art eries and one umbilical vein. In t w o cases (0.8%), t he art ery w as single. In t he t w o-vessel cor d, t he blood flow t o t he placent a is only t hrough t he single um bilical art ery result ing in a compensat ory increase of t he art erial diamet er [14].
If only one art ery and one vein are grossly visible, t he f et al anom aly r at e is nearly 50 per cent . These anom alies m ay af f ect t he cardiovascular, genit ourinary or gast rointest inal syst em and ot hers as w ell [15].
Pet er Kw abena Appiah (2009), st udied 265 umbilical cords and report ed t he average lengt h of t he cord as 44.8cms ± 12.0 [13]. And t he
st udy done by Gupt a. S, et al repor t ed t he average lengt h of the cord as 44.3cms ± 9.2 [21].
The lengt h of t he umbilical cord varies from 40-60cms and show s a t w ist of coiling. This coiling p r ov i d es gr eat er st r en gt h and n ecessar y flexibilit y. This coiling arises because t he longer um bilical vein t w ist s ar ound t he um bilical art eries and provides st rengt h and necessary t o t he umbilical vessels [21].
Principle clinical correlat ions found in over coiled cords may lead t o foet al demise, int raut erine grow t h ret ardat ion, t hrom bosis of chorionic vessels, umbilical veins and cord st enosis [11].
The umbilical cord can become knot t ed. If t he knot is loose, fet al circulat ion is maint ained. If t he knot is t ight ened during t he foet al descent t hr o u gh t he b ir t h can al , can occl ud e t h e placent al circulat ion and lead t o int raut erine deat h of t he foet us [20].
In our st udy, not iceably, w e found t hat umbilical cord had 2 art eries and 1 vein in 48 specimens w hi ch i n clu d es 39 n o r m al p r egn an ci es, 5 hypert ensive pregnancies and in 2 m ult iple pregnancies. The umbilical cord of omphalocele foet us had normal 3 vessel cord (2 art eries and 1 vein) at t ached t o t he am niot ic m embrane covering t he omphalocele at t he foet al end. In case of Trap seq u en ce t h e an ast o m osi s bet w een u m bil ical vessels w er e ob ser v ed bet w een t w in A (pump) and t w in B. The single umbilical art ery and single umbilical vein w ere observed only in 2 umbilical cords i.e. sirenomelia and Anencephalic foet uses (fig: 11.a, 13)
The present st udy w as done on 50 umbilical cords, the maximum number of cases had normal cord lengt h. The lengt h of umbilical cord in 49 specimens w as bet w een 40 t o 60cms and one specimen w it h Acardia / Acephalus t w in B had lean umbilical cord of lengt h less t han 20cms.
Our st udy finally report s t hat t he coiling and knot t ed appear ance of um bilical cord w ere w it hi n t he n or m al l im it s i n 50 sp ecim en s st udied.
CONCLUSION
examinat ion of t he placent a and umbilical cord im mediat ely aft er delivery should be used t o determine t he w ell-being of t he baby.
The morphomet ric paramet ers w ere done in 50 placent ae along wit h it s umbilical cord of normal pregnancies and abnormal pregnancies w hich also includes t w ins, hypert ensive pregnancies and f oet al anom alies. The specim ens w er e collect ed f r om p at ient s deliver ed at KIM S Hospital, Narket pally.
In t his st udy w e aim ed t o invest igat e t he morphometric charact eristics of human placenta and umbilical cord. The placent al st udy includes t he w eight , shape and at t achment of umbilical cord in bot h normal and abnormal specimens. Sim ilarly um bilical cord w as st udied in det ail regarding it s length, number of umbilical vessels, coiling and knot t ed appearance.
In an ocean of lit erat ure regarding placent a and umbilical cord, w e aut hors here by cont ribut e for a small component w hich may be useful t o Anat omist s, Embryologist s and Gynaecologist s.
The placent a is a m irror w hich reflect s t he in t r au t er in e st at u s of t h e Foet u s. Cr it ical
Conflicts of Interests: None
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