[Within the limits of viability: the dilemma of the obstetrician. A 5-year experience at a perinatal care center]. / En los límites de la viabilidad: el dilema del obstetra. Experiencia de cinco años en un Centro de Atención Perinatal.

The study was performed in order to establish the obstetric factors that influence survival of newborns whose birth weight is under 1000 g. All medical records of babies with such birth weight, born alive at the Instituto Nacional de Perinatología in Mexico City during the period from 1991 to 1996 were revised. Babies with congenital malformations, cromomosomopathies or those who after birth were referred to another medical center were excluded. Survival status was used to form two study groups: those who were discharged alive and those who died during their hospital stay. Different obstetric conditions on management were compared between these two groups. Statistical Analysis was performed through t-test, chi square or exact Fisher's test. Two hundred and ninety two cases were included out of 294. Sixty nine (25.4%) survived while 203 (74.6%) died during their hospitalization. Several obstetric conditions were found to have statistical differences between survivors (S) and non survivors (NS): cervical dilatation on admittance to hospital (1.6 cm among S and 2.7 among NS), cervical dilatation prior to resolution (3.3 cm S vs 4.9 cm NS), gestational age (28.3 vs 27 weeks). Newborn conditions also showed significant statistical differences as in birth weight (867.1 vs 795.5 g), 1 minute Apgar (4.1 vs 2.5), and 5 min Apgar (6.9 vs 5). Use of antepartum steroids showed a striking difference between groups while duration of labor, usage of oxitocin and way of delivery showed no statistical differences. Gestational age (over 28 weeks), birth weight (above 867 g) and the use of antepartum steroids are of extreme importance in the survival status of babies born weighting less than 1000 g.

[Repeat cesarean section: a necessary procedure?]. / Cesárea de repetición: Una cesárea necesaria?

The purpose of this study was to identify the clinical indications for the repeated cesarean section (RCS). In order to determine if the indication was an absolute or a relative one and to establish if it was justified. This is a cross sectional study of all patients with a previous cesarean delivery who underwent a RCS from January 1996 to December 1997 at the National Institute of Perinatology. Multiple pregnancies were excluded. According to the indication two groups were identified: those with an absolute indications and those with a relative one. In order to assess the differences between both groups data were analyzed through chi square test or Fisher's Exact test. During the study period there were 5,545 cesarean deliveries, 664 were RSC (11.9%). Only 641 of the RCS complied with the inclusion criteria for the study. Average maternal age was 30 years. More than half the patients under study (57.2%) did not have any pathological condition during pregnancy, and the rest (42.7%) had at least one (preeclampsia, diabetes mellitus/gestational, chronic hypertension). Indications for the previous cesarean section were absolute in 25.9% and relative in 74.1% (p = 0.0006). Indications for the RCS were also predominantly relative (70.7%), with only 29.3%) absolute (p = 0.0001). The main RCS indications were: elective (20.1%) cephalopelvic disproportion (17.8%), preeclampsia (15.4%), fetal distress (8%). Trial for vaginal delivery was undertaken in 65.4% of the absolute indications group and in 36.9% of the relative indications group (p = 0.0001). Low Apgar one minute and five minute scores were more frequent among the absolute indications group (p = 0.03 and p = 0.01 respectively). Newborns having had an absolute cesarean delivery indication entered the National Intensive Care Unit more frequently (53.6%) than those with relative indications (46.4%) (p = 0.001). The main indication for RCS in our hospital were relative, and thus it is possible to reduce the cesarean rate through a thorough assessment of all cases with a previous cesarean section, and by giving a delivery trial of all this patients.

[Comparative evaluation of bone mineral density in Mexican women using x-ray bone densitometry and ultrasound]. / Evaluación comparativa de la densidad mineral ósea en mujeres mexicanas entre el osteodensitómetro de rayos X y de ultrasonido.

With lifestyle changes in women, smoking and use of beverages with caffeine, and sedentarism increasing, so the risk factors for decalcification, increase; which is a public health problem by the higher incidence of osteoporotic fractures, as the age advances, specially in the postmenopause woman, which means a greater secondary morbidity-mortality; an important cause of physical disability, which directly affects psychoemotional wellbeing in women. In this study two methods of bone densitometry, were used; one of x ray, and other with ultrasound in 138 women during postmenopause with an average index of corporal mass of 29. Both results were compared of bone density, T measurement with osteopenia and osteoporosis. Double densitometry, was done in the 138 patients of lumbar spine with DEXA equipment, and of calcaneum with DTU-one equipment, by the same technician, finding the difference of T punctuation in this double study.

[Obstetric decisions concerning adolescents vs. adults]. / La resolución obstétrica de las adolescentes en comparación con la de las adultas.

Information relative to the frequency of vaginal delivery and cesarean section in adolescent population is limited and contradictory. Some publications refer that cesarean section is practiced more frequently in adolescents than in adults, because teenagers have a biological immaturity and a less medical control during pregnancy; but others show that frequency of cesarean section and vaginal delivery is very similar in adolescents as in adults. The reason of this contradiction is the fact that all studies compare general populations, with or without sistemic pathologies, and with or without obstetric antecedents. Therefore, the authors of this paper consider that if they compare adolescent and adult populations in their first pregnancy and without sistemic pathologies, the frequency of cesarean section and vaginal delivery should be the same in the two groups of women. To confirm their hypothesis, the authors collected original data from 121 adolescent women in their first pregnancy, seventeen years old or younger, without sistemic pathology, attended in the Instituto Nacional de Perinatología, and they compared them with original data collected from 121 adult women also in their first pregnancy, between 20 to 27 years old, without sistemic pathology, attended in the same institution and during the same period. The authors concluded that there were not statistical differences between the two groups in relation to the number of prenatal care visits; the weeks of pregnancy at the time of delivery; the indications of the different obstetric procedures to resolve the delivery; and in the perinatal mortality. Nevertheless, there were differences with high statistical significance between the number of vaginal deliveries and the number of cesarean sections; in fact, the cesarean section was performed more frequently in adult women. The authors considered that in the population of adolescents they studied, the age by itself was not a risk factor; furthermore, it is necessary to perform other studies to confirm and to explain why the cesarean section was performed more frequently in the adult population.

[Trends of perinatal mortality at the National Institute of Perinatology]. / Tendencias de la mortalidad perinatal en el Instituto Nacional de Perinatología.

The purpose of this study is to address the yearly fetal, neonatal, crude death rates observed at the Instituto Nacional de Perinatología from 1987 through 1997, and the specific death rates for birth weight, gestation age, cause of death, avoidability, and structure and process failures as proxy to quality of medical care. Data come from death certificates following the WHO criteria which includes the maternal medical history, pregnancy follow up, birth attendance, newborn characteristics, autopsy findings, microbiological results, basic cause of death (of both maternal and fetal/neonatal origin), death avoidability, and structure and process issues. The death certificates were analyzed by the Perinatal Mortality Committee and registered into a computerized database. The fetal mortality rate during 1987 was 17.67 per 1000 births, whereas in 1997 it was 21.5 per 1000 births. There was an increasing tendency from 1987 to 1992, with the highest rate being 34.13 during 1992. After 1992 this rate shows a decreasing tendency. The neonatal mortality rate decreased from 42.82 in 1987 to 17.34 per 1000 live births in 1997. The highest rates were observed among the newborns with the lowest birth weights and at the youngest gestational ages. The most frequent cause of death of maternal origin, in both fetal and neonatal deaths, was premature rupture of membranes. As for the most frequent fetal cause of death was antepartum hypoxia, and among neonatal deaths prematurity and immaturity. The percentage of avoidable perinatal deaths has declined dramatically from 27% in 1987 to less than 10% in 1996. Perinatal mortality at the Instituto Nacional de Perinatología has decreased during the period under assessment, due to the reduction of the neonatal mortality rate. Improving the quality of medical care focusing mainly on process issues will help lowering avoidable mortality rates.

[Epidemiologic characteristics in women with sterility and cervical lesions with and without human papilloma virus infection. Comparative study]. / Características epidemiológicas en mujeres con esterilidad y lesiones cervicales con y sin infección por virus de papiloma humano (VPH). Estudio comparativo.

Human papilloma virus (HPV) infections frequently cause cervical lesions of different morphologies. We have previously reported a 53.5% pregnancy rate after treatment in a group of women with infertility associated to HPV infection of the cervix uteri. In that paper it was stated that a controlled study should be conducted in order to confirm this finding. Present work was aimed to find if there is any correlation between HPV infections of the cervix uteri and infertility in a retrospective design using an historical cohort of patients studied between 1991 and 1996 in our clinic. A total of 61 women attending the Infertility Clinic at the Instituto Nacional de Perinatología were included into two group. Group 1 (n = 45) included women with HPV lesions of the cervix and group II (n = 16) was formed by women with other type of cervical lesions who had no evidence of HPV infections on colposcopy. Cervico-vaginal citology, colposcopyc study and biopsy specimens were evaluated in all this medical records and the patients status (pregnant-not pregnant) at one year after treatment was registered. The mean duration time of infertility was 4.86 in group I and 3.5 in group II. Pregnancy rate was 16/45 (35.55%) in group I and 6/16 (37.5%) in group II. Seventy five percent of patients in group I and 66% in group II achieved a spontaneous pregnancy after specific treatment of cervical lesions whereas 25% and 33.3% required only ovarian stimulation with clomiphene or hMG. Pregnancies occurred approximately at 9 months after treatment in group I and at 7 months in group II. An association of cervical lesions and a tuboperitoneal factor (excluding endometriosis) was found on 53.57% of women in group I and on 46.66% of women in group II. Cervico-vaginal cytology was suspicious of HPV infection in less than 25% of cases. Present study emphasizes the need for a colposcopic study for the diagnosis of HPV infection in infertile women with cervical lesions even in cases with a negative cervico-vaginal cytology; because specific treatment of these lesions may yield spontaneous pregnancies. It also demonstrates that around 50% of patients with cervical lesions have an associated tuboperitoneal factor, which indicates that it is mandatory to study the possible participation of viral infections on tubal pathology.

[Advanced maternal age and pregnancy: how much is too much?]. / Edad materna avanzada y embarazo: qué tanto es tanto?

Perinatal evolution was compared and two study groups in women with advanced maternal age and pregnancy. 626 were included from a total of 778 with age 35 years, who resolved their pregnancy during 1995. They were classified, according to age, in two groups: 1) maternal age of 35-39 year; they were considered primigestas and multigestas. Perinatal complications were classified in personal antecedent, antepartum and intrapartum complications. To analyze the association between maternal age and parity with perinatal complications, X2 or exact test of Fisher, was used. Percentage of women with advanced age and pregnancy was 13.6%. Main perinatal complications were: preeclapmsia, gestational diabetes, preterm delivery threat, and membranes rupture. There were no significant differences as to complications by age and parity. There were 90% of children with 2500 g, and Apgar of 97%. Perinatal death was 0.4%, and fetal malformation 0.6%. Cesarean frequency, was over 90% in primigestas and in more of 60% in multigestas. Perinatal evolution in advanced age and pregnancy is adequate, if she starts prenatal control early enough.

Comparison of two methods for the discrimination of avoidable perinatal deaths.

This paper analyzes the validity and reliability of a method proposed by HERMAN et al [8] used to classify avoidable neonatal deaths. This method is based on a list of amenable medical conditions with an a priori decision about the avoidance of deaths. The results obtained using this method are compared to those derived from the discussion of individual cases by a committee created ex profeso. The population under study includes all neonatal deaths occurred at a third level hospital in Mexico City, from January 1, 1987 to July 31, 1994 (n = 1337). Only 56% of neonatal deaths could follow HERMAN's classification (n = 749). Poor concordance (Cohen's Kappa = 0.30) between the two methods was found. A high proportion of deaths (72.7%) was classified ambiguously (as possibly preventable), and also a considerable proportion of deaths could not be classified (44%). High sensitivity (96%) was found for the small percentage of cases in which avoidance was determined by the method under assessment (15%). A priori classification is useful for developing rough quality indicators at the regional level but not at hospital settings.

PIP: Two methods for the identification of avoidable perinatal deaths (the first based on a Perinatal Mortality Committee [COMOPer] audit using the Ninth Revision of the International Disease Classification and the second on a computerized list developed by Herman et al.] were compared through use of data from the National Institute of Perinatology in Mexico City, Mexico. While the Herman method entails an a priori determination about the avoidability of deaths by cause, the other is derived from a discussion of individual cases by a committee of experts. Analyzed were the 1337 neonatal deaths occurring at the institution during 1987-94; fetal and infant deaths were excluded because of their lack of fit with the Herman model. Of the 749 neonatal deaths (56%) in which Herman's list could be applied, 173 were classified as avoidable, 541 as possibly avoidable, and 35 as nonavoidable. In contrast, COMOPer designated 230 of these same deaths as avoidable, 514 as nonavoidable, and 5 as undeterminable. Only 38% of neonatal deaths assessed by COMOPer as avoidable and 6% of those judged unavoidable were so classified by the Herman method. This extremely low concordance (Cohen's Kappa, 0.30) indicates the importance of a case-by-case analysis that takes into account the factors underlying the most frequent local pathologies as well as local health policies (e.g., the legality of abortion). Although an a priori classification system can enable the assessment of rough indicators of the quality of medical care at a regional level, a careful analysis of individual deaths by a multidisciplinary group of experts is important to identify deficiencies in the quality of care at the local hospital level.

The effectiveness of antenatal care in preventing intrauterine growth retardation and low birth weight due to preterm delivery.

A case-control study was conducted to assess the effectiveness of antenatal care in preventing intrauterine growth retardation (IUGR) and low birth weight due to preterm delivery (PD), using data from 1837 births which took place in 25 hospitals in Mexico City during 1984. Women with an inadequate number of visits for gestational age had 63% greater odds of IUGR (95% CI: 1.01, 2.65) and 51% greater odds of PD (95% CI: 1.02, 2.23) than women with an adequate number. The content of antenatal visits showed no independent effect on the prevention of IUGR. Women having had poor content showed a PD OR of 1.76 (95% IC: 1.33, 2.34). An important reduction in the incidence of births with IUGR and PD could be expected if women could attend an adequate number of antenatal visits (11 and 9% reductions, respectively). Eighteen per cent of the PD births would probably be prevented if antenatal care could include at least six procedures: blood pressure, height and weight, urine and blood samples, and pelvic examination.

[The evaluation of the usefulness of ultrasound independent of estradiol as a prognostic criterion for ovular capture and maturity. A comparative double-blind study]. / Evaluación de la utilidad del ultrasonido independiente de estradiol como criterio pronóstico para captura y madurez ovular. Estudio comparativo doblemente ciego.

One hundred and twenty women were studied which had primary or secondary sterility, and underwent into the GIFT or IVF-ET program at the INPer. They were divided in two groups. Group I had 96 women in which only was taken in account the follicular development measured by vaginal ultrasound to decide continuation or cancellation, in this group estradiol serum levels determination was done, but it was not used for decision making; group II had 24 women in which estradiol was taken in account in addition with ultrasound. There were no differences in the number of follicles seen by ultrasound neither in the estradiol serum levels between the groups. Correlation coefficients between follicles seen by ultrasound and retrieved oocytes and mature oocytes, thus partial correlation coefficients for follicles seen by ultrasound plus estradiol serum levels and retrieved oocytes and captured oocytes were higher in group I in all days with the exception of day 10 in which they were similar. By the aforementioned in can be concluded that in this group of patients the ultrasound was the most reliable variable to give a quantitative and qualitative prognostic of oocyte retrieval.

[Maxillofacial anthropometry tables in healthy newborns]. / Tablas de antropometría maxilofacial en recién nacidos sanos.

With the purpose of having parameters which can be useful to evaluate the maxillofacial anthropometric characteristics at birth, we present the results of maxillofacial anthropometric measurements of 22 items in 373 healthy eutrophic newborns of both sexes delivered at the National Institute of Perinatology in Mexico City. Minor alterations of facial structures may indicate the presence of a dysmorphological syndrome such as: wide nasal bridge and wide intercantal distance. This study did not show big increments in the different anthropometric measurements from one week of gestation to the next, except for the bizygomatic and intercommissural measurements.