Carbohydrate metabolism was evaluated in 26 women with a twin pregnancy and 26 women with a singleton pregnancy. The groups were similar in respect of age, parity and gestational age. Each woman had an oral glucose tolerance test. Nosignificant differences in venous blood sugar values or insulin responses were found between singleton and twin pregnancies

Jialal, I.

Moodley, J.

Naicker, R.S.

Subrayen, K. T.

Van Middelkoop, A

English

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538 SA MEDICAL JOURNAL VOLUME 63 2 APRIL 1983Carbohydra~epregnancymetabolism •In. .tWInR. S. NAICKER, K. T. SUBRAYEN, I. JIALAL, J. MOODLEY,A. VAN MIDDELKOOPSummaryCarbohydrate metabolism was evaluated in 26women with a twin pregnancy and 26 women with asingleton pregnancy. The groups were similar inrespect of age, parity and gestational age. Eachwoman had an oral glucose tolerance test. No signi-. ficant differences in venous blood sugar values orinsulin responses were found between singletonand twin pregnancies.S Atr Med J 1983; 63: 53&-540.It is well known that pregnancy is associated with alterations incarbohydrate metabolism. These changes are best reflected byblood glucose and insulin patterns. Fasting blood glucose levelsbecome slightly lower during pregnancy, whereas plasma insulinlevels after a glucose challenge are significantly elevated, mostmarkedly so towards the end of gestation. 1 Pregnancy is there-fore associated with a decreased sensitivity to insulin. The causeof this insulin insensitivity in pregnancy is Unknown, but onepossible explanation is the rise in the level of human placentallactogen (HPL) that accompanies gestation.2Spellacy er aP showed that HPL levels are even higher inpregnancies with two or more placentas. Subsequently, in astudy ofcarbohydrate metabolism in twin pregnancies, Spellacyel al. 4 using an intravenous glucose tolerance test (GTT) showedthat HPL levels were significantly higher and fasting glucoselevels were significantly lower in women with twin pregnanciesas compared with singleton pregnancies.The present study was undertaken to determine: (/) whethercarbohydrate metabolism as determined by an oral GTT wassignificantly altered in twin pregnancy as compared with sin-gleton pregnancies at "the same gestation; and (i/) the nature ofthe relationship between blood glucose, insulin and HPL levelsin twin gestation.Patients and methodsInformed consent was obtained from 52 Black women in the lasttrimester of pregnancy who were attending the antenatal clinic atDepartments of Obstetrics and Gynaecology and ChemicalPathology, University of Natal, DurbanR. S. NAICKER, M.RCO.G.,ConsulcamK. T. SUBRAYEN, M.B. CH.B.,Registrar1. JIALAL, M.B. CH.B.,Senior RegistrarJ. MOODLEY, M.R.CO.G., F.CO.G. (SA), ConsulcamA. VAN MIDDELKOOP, B.SC (AGRIC),SwtiSlicianDate received: 9 June 1982.Reprint requests to: Or J. Moodley, Dept of Obstetrics and Gynaecology, University of r\atalMedical School, PO Box 17039, Congella, 4013 RSA.King Edward VIII Hospital, Durban, and were quite sure of thedate of their last menstrual period. .Twenty-six women had the diagnosis of twin pregnancy con-firmed by ultrasonography after multiple pregnancy ~as sus-pected on clinical grounds. The other 26 had singleton pregnan-cies. Both groups were matched for age, parity, 'weight andgestational age. None of the women included in the study was onany form of drug therapy except for prophylactic iron andvitamin therapy. The subjects were encouraged to partake of ahigh carbohydate diet for at least 1 week prior to the GTT.After the overnight fast venous blood samples. were withdrawnfrom a peripheral vein in which a 'butterfly cannula' wasinserted. The cannula was flushed and kept open with a solutionof heparinized saline. Blood samples were taken for gluco~e,insulin and HPL estimations initially. A 50 g glucose.load dIS-solved in 300 ml water was given to the patient and blood samplesfor glucose and insulin were withdrawn at half-hourly intervalsfor 3 hours.Laboratory methodsThe samples for glucose were taken in tubes containingsodium fluoride and potassium oxalate while the specimens forinsulin and HPL were taken in tubes containing no preservative.Plasma glucose was measured by the ferricyanide method on theAutoAnalyzer.5 HPL was assayed in duplicate by radio-immuno-assay techniques (Radiochemical Centre, Amersham, VK).. Serum insulin levels were measured in duplicate by a radio-immunoassay in which the antibody was coupled to a solid phase(Pharmacia, Vppsala, Sweden). A control was incorporated ineach assay undertaken.Statistical analysisThe areas under the insulin and glucose curves were computedaccording to the method of Chiles and Tzagoumis.6The glucose results were analysed with Student's I test; theinsulin data, following a positively skewed distribution, wereanalysed with the Mann-Whitney U test.ResultsThe characteristics of the two groups are shown in Table I.Plasma HPL levels were significant!y higher in women withtwin pregnancies than in women with singleton pregnancies.Plasma glucose response. Analysis of the blood glucoseresults is shown in Table 11 and Fig. 1. There was no significantdifference between the two groups throughout the period oftesting. . . .Plasma insulin response. Analysis of the plasma Insulinresponses is shown in Table III and Fig. 2. Although at mostpoints the values tended to be lower for the tWIn preg!1ancygroup, these differences did not attain significance. Further-more while the area under the insulin curve in the twin group(5790 J.L V/min) was lower than in the singleton pregnancies(7080 J.L V / min) this did not attain significance at the 5% level(0,1 > P > 0,05).SA MEDIESE TYDSKRIF DEEL 63 2 APRIL 1983 539'Results expressed as mean =SO. Groups compared using Student's r test.+Result expressed as median (minimum - maximum). Groups compared using theMann-Whitney U test.Signi-ficanceP>O,20P>O,20P >0,05P>O,20P> 0,20P > 0,20P> 0,200,10> P>0,055790(1810 - 15315)Twin14,0 (8,7 - 36,0) 12,6 (5,0 - 60,0)48,0 (12,0 - 145,0) 43,0 (6,5 - 160,0)48,S (24,0 -110,0) 39,S (8,7 -135,0)37,S (15,0 - 132,0) 34,S (12,0 - 100,0)30,0 (11,0 - 164,0) 35,0 (8,0 - 65,0)21,S (10,8 - 116,0) 20,0 (7,0 - 50,0)13,5 (7,4 - 54,0) 14,0 (1,5 - 33,0)SingletonTimeFasting'/2 h1 h1' / 2 h2h2' / 2 h3hArea underinsulin curve 7080(/lUlmin) (4380 - 19560)TABLE Ill. ANALYSIS OF THE PLASMA INSULIN (/lU/ml)DURING AN ORAL GTT'P>O,20P>O,oolSignificanceP>O,20P>O,20P>O,2034,1 ± 2,98,5 ± 1,633,6 ± 3,15,8 ± 1,4TABLE I. CHARACTERISTICS OF THE TWO GROUPSIN THE STUDYSingleton Twin26,3 ± 5,9 26,2 ± 5,52 (0 - 7) 1,5 (0 - 7)71,8 ± 11,1 74,9 ± 18,6Age (yrs)'ParitytWeight (kg)'Gestational age(wks)'HPL (/lg/ml)'- - - To....in pregnancieswhere the incidence of multiple pregnancy is very high (lout of26 pregnancies) the clinical impression is that the frequency ofcarbohydrate intolerance is not increased in multiple pregnancy.Spellacy er al. 4 also showed that the woman carrying twins isnot at higher risk ofclinical hyperglycaemia. They performed anintravenous GTf using a 25 g glucose load on 24 women withtwin gestation and found no difference in glucose and insulinprofiles when compared with a group of 24 women withsingleton pregnancies matched for age, parity, weight and gesta-tional age. One of the criticisms of their study is the use of theintravenous GTf. Arguments for its use are that it gives valuesmore influenced by glucose disposal than the oral GTT, bothvariations in rate of absorption and the problem of nausea fromingestion of glucose being avoided. However, most extensivestudies for detecting gestational diabetes have used the oralGTf, and it would seem that its use has become firmlyentrenched. More importantly, the oral GTf is more physiolo-gical since absorption of glucose is a necessary stimulus for theentero-insular axis which is pari of the total metabolic cyclebeing tested.The present study was therefore undertaken to determine ifthere was an alteration in carbohydrate metabolism in twinpregnancy using the 50 g oral GTT. No significant differences invenous blood sugar or insulin profiles were found betweensingleton and twin gestations, which supports the clinicalimpression that the woman carrying twins is not usually at high"Results expressed as median (mmimum - maximum). Groups compared usingMann-Whitney U test.Fig. 2. Plasma insulin levels during an oral GTT.---- Singlec.or. f-regnanciesTime (hours)50.~5-4000~~>~.~ 30~~.~'" 20~'"~.~':1"~"0P >0,20985,85±133,47TABLE 11. ANALYSIS OF THE BLOOD GLUCOSE LEVELS(mmol/I) DURING AN ORAL GTT'Singleton Twin Significance4,20 ± 0,51 3,96 ± 0,56 0,10> P > 0,056,35 ± 1,17 6,00 ± 1,07 P> 0,206,72 ± 1,22 6,47 ± 1,02 P> 0,206,06 ± 1,27 6,00 ± 1,07 P > 0,205,33 ± 1,27 5,55 ± 1,02 P > 0,204,52 ± 1,07 4,88 ± 1,10 P> 0,203,93 ± 1,12 4,06 ± 1,02 P> 0,20TimeFasting'/2 h1 h11/ 2 h2h2' / 2 h3hArea underglucose curve(mmol/min) 993,52±135,38---- Singleton pregnancies- - - Twin pregnancies"Results expressed as mean I SD. Groups compared using Student's t test.o~ """'__--IoT itr.e (hours)A brief survey of the literature on carbohydrate metabolism inmultiple gestation shows very little data on this subject. MacGil-livray er al. 7 point out that chemical gestational diabetes is morecommon in wpmen with twin pregnancy and recommend that allwomen with multiple gestation have a GTf in the third trimes-ter of pregnancy. However, at King Edward VIII Hospital,Correlations between HPL and glucose and insulinareas. There was no significant correlation between the HPLlevels and the areas under the insulin curve (r = - 0,33; P > 0,05)and between HPL and glucose curves (r =0,15; P > 0,05).Fig. 1. Blood glucose levels during an oral GTT.Discussion540 SA MEDICAL JOURNAL VOLUME 63 2 APRIL 1983risk of clinical hyperglycaemia. There was a tendency howeverfor the insulin levels to be lower in multiple than in singletonpregnancies. These results are very similar to those of Spellacy elal. 4 Why these changes occur is difficult to define; the alteredhormonal milieu of pregnancy is usually held to be responsibleand this is probably so. Certainly the changes revert to normaLBOne of the many explanations for the high levels of insulin inpregnancy is the rise in HPL levels that accompanies gestation.HPL has been described as having a 'diabetogenic' effect.Beck and Daughaday9 infused non-pregnant women withHPL and demonstrated an impairment in glucose tolerancetogether with an increased insulin response. However, the HPLhad to be given by infusion for a minimum of 12 hours and someof the subjects had an unusual response to an oral glucose loadprior to the investigation. Despite reservations about this study,HPL is regarded by many authors as a major factor causinginsulin resistance in pregnancy. HPL levels are even higher inmultiple gestations; the belief therefore arises that twin gesta-tions have a high incidence of diabetes. The present study doesconfirm that HPL levels are much higher in women carryingtwins than in those with singleton pregnancies (P < 0,001) butthere was no demonstrable relationship between HPL levels andglucose and insulin profiles in either group. Thus it would be anover-simplification to hold anyone hormone, such as HPL,responsible for the carbohydrate intolerance in pregnancy; thewhole complex ofaltered maternal adaptations, including changesin protein and fat metabolism, probably combine to influencechanges in ~arbohydrate metabolism.This work was supported by the South African Medical ResearchCouncil through the Preclinical Diagnostic Chemistry ResearchGroup.REFERENCES1. Spellacy WN, Goetz FC Plasma insulin in normal late pregnancy. N Engl]Med 1963; 268: 288.2. Lind T, Bume J M, Kuhl Je. Metabolic changes in pregnancy relevant 10diabetes. In: Sutherland HW, SlOwer JM, eds. Carbohydrare Metabolism inPregnancy and the Ne'"d'bom. Berlin: Springer, 1978. •3. Spellacy WN, Buhi WC, Birk SA. Human placentallaclOgen levels in multiplepregnancy. Ob"et Gynecol1978; 52: 210.4. Spellacy WN, Buhi WC, Birk SA. Carbohydrate metabolism in women with atwin pregnancy. Obsm Gynecol1980; 55: 688-691.5. Hoffman WS. Rapid photoelectric method for determination of glucose inblood and urine.] Bioi Chem 1937; 51: 121.6. Chiles R, Tzagouris M. Excessive serum insulin response to oral glucose inobesit\' and mild diabetes. Diabeus 1970; 19: 458-464.7. MacGillivray I, Nyalander PPS, Lomey L. Human Muiliple ReproduClion.London: WB Saunders,. 1975: 15.8. Lind T, Harris VG. Changes in the oral glucose tolerance test during thepuerperium. Br] Ob"et Gynaecol 1976; 83: 460-463.9. Beck P, Daughaday WHo Human placental lactogen: studies of its acutemetabolic effecls in normal women.] Clin [rruest 1967; 46: 103-110.The Zulu traditional birth attendantAn evaluation of her attitudes and techniques and their implications forhealth educationJ. V. LARSEN, C. L. MSANE, M.C.MONKHESummarySome of the important practices of Zulu traditionalbirth attendants in their care of pregnant women aresummarized. This. information is valuable in con-structing the format/content of appropriate antena-tal health education for women from rural areas.The target group for antenatal health educationshould include the opinion-formers of the com-munity.S Air Med J 1983: 63: 54(}-542.Department of Obstetrics and Gynaecology, King EdwardVIII Hospital, DurbanJ. V. LARSEN, .\1.R.C.O.G.. Principal Specialise (Present address:I Havelock Street, Eshowe, Kwazulu)KwaMakutha Clinic, KwazuluC. L. MSANE, S.RS.. S.R..\I .. AO\·. DIPL. .\lto\'rlF. :\EO:\.H. :\l·RS. SC!.G. J. Crookes Hospital, Scotlburgh, NatalNi. C.1\10NKHE, S.RS.,S.R ..\I..AOY. OIPl...\\ID\X·IF. :\EO:\AT. :\l·RS. SC!.Dare- recein:d: 11 _\lan.:h 1982.Obstetricians working among rural communities in Africa areoften confronted by behaviour unfavourable to health among thewomen using the health facilities that they service. The frus-trated doctor may respond to this behaviour with anger and evenridicule unless he is initiated into some ofthe cultural insights ofthe people as regards pregnancy and labour. This article docu-ments insights gained during 2 years of contact with a group of 5Zulu traditional birth attendants (TBAs), who live in the magis-terial district of Vulamehlo, which is 80 km soulh of Durban.Material and methodsA queslionnaire based on one used in Ghana' was constructed bythe authors with suitable modifications. The TBAs met with theauthors for a morning (from 08h30 to l3hOO) every fortnightduring 1980, and less regularly during 1981. The questionnairewas administered by two of the authors (C.L.M. and M.C.M.)and a consensus of views was recorded.ResultsAntenatal careThere is no tradition among Zulu TBAs which involves physi-

Carbohydrate metabolism in twin pregnancy

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Carbohydrate metabolism in twin pregnancy

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