Anders Selbing

Intrauterine growth curves based on ultrasonically estimated foetal weights

Available standard intrauterine growth curves based on birthweights underestimate foetal growth in preterm period. New growth curves are presented based on data from four Scandinavian centres for 759 ultrasonically estimated foetal weights in 86 uncomplicated pregnancies. Mean weight of boys exceeded that of girls by 2‐3%. A uniform SD value of 12% of the mean weight was adopted for the standard curves as the true SD varied non‐systematically between 9.1 and 12.4%. Applied to an unselected population of 8663 singleton births, before 210 days of gestation, 32% of birthweights were classified as small‐for‐gestational age (SGA; i.e. below mean ‐2SD); the corresponding figures were 11.1% for gestational ages between 210 and 258 days, and 2.6% for ages of 259 days or longer. The new growth curves reveal better the true distribution of SGA foetuses and neonates, and are suggested for use in perinatological practice.

Children born after cryopreservation of embryos or oocytes: a systematic review of outcome data

BACKGROUND An estimated 3.5 million children have been born to date using assisted reproduction technologies. We reviewed the data in order to evaluate current knowledge of medical outcome for IVF/ICSI children born after cryopreservation, slow freezing and vitrification of early cleavage stage embryos, blastocysts and oocytes. METHODS A systematic review was performed. We searched the PubMed, Cochrane and Embase databases from 1984 to September 2008. Inclusion criteria for slow freezing of early cleavage stage embryos were controlled studies reporting perinatal or child outcomes. For slow freezing and vitrification of blastocysts and oocytes, and vitrification of early cleavage stage embryos, case reports on perinatal or child outcomes were also included. Three reviewers independently read and evaluated all selected studies. RESULTS For early cleavage embryos, data from controlled studies indicated a better or at least as good obstetric outcome, measured as preterm birth and low birthweight for children born after cryopreservation, as compared with children born after fresh cycles. Most studies found comparable malformation rates between frozen and fresh IVF/ICSI. For slow freezing of blastocysts and for vitrification of early cleavage stage embryos, blastocysts and oocytes, limited neonatal data was reported. We found no long-term child follow-up data for any cryopreservation technique. CONCLUSION Data concerning infant outcome after slow freezing of embryos was reassuring. Properly controlled follow-up studies of neonatal outcome are needed after slow freezing of blastocysts and after vitrification of early cleavage stage embryos, blastocysts and oocytes. In addition, child long-term follow-up studies for all cryopreservation techniques are essential.

Placental transport of maternal immunoglobulin G

PROBLEM: How does the placental transport of immunoglobulin G (IgG) vary with gestational age?

Detection of fetal structural abnormalities by an 11-14-week ultrasound dating scan in an unselected Swedish population

Background. To determine the detection rate of fetal structural abnormalities by a routine 11–14‐week ultrasound scan for dating in an unselected pregnant population. Methods. A prospective observational cohort study of 2,708 unselected pregnant women attending an abdominal ultrasound examination at 11–14 weeks gestation. The number of major fetal structural abnormalities diagnosed after birth was obtained from a computerized database at the same unit. Results. Out of 2,708 pregnant women, 89 (3.3%) were found to have a missed abortion at the time of the ultrasound scan and 33 (1.2%) were diagnosed as twins. Thirteen major structural abnormalities were detected, three cases of anencephaly (one case also had a spina bifida), one case with hydranencephaly, one fetus with Dandy‐Walker syndrome, two cases with gastroschisis, one case with a bilateral hydronephrosis, one case with a generalized hydrops, one fetus with multiple malformations, and three cystic hygromas. An additional 19 major structural defects were detected at birth. Four cases of neural tube defects and nine fetuses with congenital heart defects were diagnosed. The antenatal ultrasound detection rate was 40.6% (13/32). Nine patients had a nuchal translucency greater than 3.0 mm (excluding cystic hygromas); two of them had chromosomal abnormalities (trisomy 21 and trisomy 18). Conclusions. Fetal structural abnormalities were detected in 41% (95%CI = 24–59) of the cases in an unselected pregnant population at a routine 11–14‐week ultrasound scan for dating purpose. Two out of nine fetuses with a nuchal translucency greater than 3.0 mm had a chromosomal abnormality.

CONCEPTUAL DATING BY ULTRASONIC MEASUREMENT OF THE FETAL BIPARIETAL DIAMETER IN EARLY PREGNANCY

Abstract. The accuracy and precision of gestational dating, based on single measurements of the fetal biparietal diameter (BPD), was estimated in a consecutive series of 970 apparently normal, singleton pregnancies. The BPD sizes used varied between 11 and 60 mm, corresponding to 9–22 postconceptional weeks. The ‘conceptual ages’, used for reference, were estimated by means of ultrasonic measurements of the fetal crown—rump lengths (CRL). The association between the estimated conceptual age (dependent variable) and BPD size (independent variable) was found to be well represented (R2 = 0.972) by a second order polynomial: conceptual age = 44.7 + 1.069 × BPD+ 0.01382 × BPD × BPD. To check the validity of the proposed equation, we used 23 fetuses conceived by artificial insemination with donor semen as controls. There was good agreement between the virtual conceptual ages of the control cases and their corresponding BPD‐estimated conceptual ages (0.5 days mean difference, 3.6 days SD) when the suggested regression equation was used. The estimated precision of BPD‐dating was minumum ±4.4 days (= ±2SD) at 9–10 completed postconceptional weeks. At 14 completed weeks the corresponding precision was found to be ±11 days (±2SD). At the end of the studied BPD size interval, i.e. 56–60 mm BPD corresponding to 22 conceptual weeks, the precision was ±15 days. From an obstetrical point of view it seems obvious that the imprecision of gestational dating associated with BPD measurements > 35 mm should call for ultrasonic dating procedures to be performed earlier in pregnancy. An optimal precision of dating, i.e. better than ±6 days (= ±2SD), will certainly be achieved by ultrasonic measurements of the BPD between the 9th and 12th completed postconceptional weeks.

Nuchal translucency as a screening test for chromosomal abnormalities in a routine first trimester ultrasound examination

BACKGROUND To evaluate the implementation of nuchal translucency measurement as an additional examination within the first trimester routine ultrasound in an unselected population of women. METHODS A prospective study in which all pregnant women during 1994, referred for the first trimester routine ultrasound scan, were asked to participate. Of a total of 1852 women with a viable pregnancy, results from 1444 women were evaluated. When a nuchal translucency of 4 mm or more was found, the woman was offered both a genetic amniocentesis in gestational week 13-15 and an additional ultrasound examination in gestational week 18-19. RESULTS Six fetuses had a nuchal translucency of 4 mm or more and none of these had any chromosomal abnormality. Neither had any of the fetuses in the study, karyotyped for other reasons, any chromosomal defect and nor was there any child born with aneuploidy in the study population. No strong relation between major malformations e.g. abnormalities of the heart and increased nuchal translucency was found. The fetus with the largest nuchal translucency (=6 mm) was born healthy. CONCLUSION The efficacy of nuchal translucency measurement needs further evaluation before it can be introduced as a screening method in an unselected pregnant population.

Evaluation of a new Swedish protocol for alloimmunization screening during pregnancy.

Screening protocols for alloimmunization during pregnancy usually make a difference between primi‐ and multigravidae as well as between Rh(D) negative and Rh(D) positive pregnant women. We have evaluated a new screening program including antibody tests at 25 and 35 gestational weeks only, for all, and regardless of Rh(D) group. During the time period 1983–89, 78,300 consecutive pregnancies were tested. Red cell antibody immunizations were detected in 287 (0.37%) pregnancies subdivided into fourteen different red cell IgG antibody specificities. Significant antibody titers (defined as IAT or enzyme titers ≤8) were observed in 225 pregnancies, where 127 (56%) were previously unknown. A majority (63%) of the new immunizations occurred among the Rh(D) positive pregnant women. All newborns that needed phototherapy or exchange transfusion due to alloimmunization were recognized at the time of delivery. We conclude that antibody screening tests at 25 and 35 gestational weeks for both Rh(D) negative and positive pregnant women is sufficient, effective and a safe procedure for the fetus as well as for the mother.

Comparison of first and second trimester ultrasound screening for fetal anomalies in the southeast region of Sweden

Objective. To assess and compare the sensitivity for detecting fetal anomalies and chromosomal aberrations by routine ultrasound examination performed in the second trimester with results from an examination performed at 11–14 weeks gestation. Design. Observational study. Setting. Five centers in the southeast region of Sweden. Population. A total of 21,189 unselected pregnant women. Methods. The scan was performed at one center in the first trimester and at the remaining four centers in the second trimester. Outcome measures resulting from first trimester scanning were compared with those from the second trimester scanning. Main outcome measures. Detection rates of fetal structural anomalies and chromosomal aberrations. Results. At the first trimester scan 13% of all anomalies were detected, and at the second trimester scan 29% were detected. Lethal anomalies were detected at a high level at both times: 88% in the first, 92% in the second. The percentage of chromosomal aberrations discovered at the early scan was 71%, in the later 42%. The percentage of heart malformations detected was surprisingly low. Conclusion. The results showed the advantages of the later scan in discovering anomalies of the heart, urinary tract and CNS, and of the early scan in discovering chromosomal aberrations. Lethal malformations were detected at a high level in both groups, but detection of heart malformations needs improvement.

Alloimmunization during pregnancy treated with high dose intravenous immunoglobulin. Effects on fetal hemoglobin concentration and anti-D concentrations in the mother and fetus.

Background. High dose intravenous immunoglobulin has been reported to be advantageous in the treatment of alloimmunization during pregnancy. The mode of action is unknown.

Blocking Antibodies in Blood from Patients with Recurrent Spontaneous Abortion in Relation to Pregnancy Outcome and Intravenous Immunoglobulin Treatment

PROBLEM: To study whether the occurrence of mixed lymphocyte culture (MLC) blocking antibodies is associated with pregnancy outcome in women with unexplained recurrent spontaneous abortion (RSA) and the in vivo effect of intravenous immunoglobulin (IVIG) treatment on MLC blocking effect.
 METHOD OF STUDY: Blood samples from 41 RSA patients were obtained before and after pregnancy, and blocking antibodies were estimated by one‐way MLC assay. The patients received IVIG or placebo (saline) during pregnancy. Additionally, pre‐pregnancy blood samples from 31 RSA women and 10 controls were obtained.
 RESULTS: We found no correlation between blocking antibodies before pregnancy and the pregnancy outcome. The occurrence of blocking antibodies was not affected by pregnancy or IVIG treatment.
 CONCLUSIONS: Blocking antibodies have no predictive value for the pregnancy outcome in RSA patients, and their production seems not to be affected by IVIG.