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Original Research

First-Trimester and Second-Trimester Screening at a Community Hospital: Experience From the First Year of Implementation

Philipson, Elliot H. MD; Callahan, Michelle RN; Jelovsek, J Eric MD

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doi: 10.1097/AOG.0b013e31817e7c32
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Contemporary prenatal risk assessment for aneuploidy has evolved far beyond using maternal age and historical criteria as a basis for screening.1–3 Recent multicenter clinical trials have clearly demonstrated that assessment of nuchal translucency and biochemical markers in the first trimester, either alone or in conjunction with traditional second-trimester screening, clearly improves the sensitivity and specificity for detecting Down syndrome and other chromosomal abnormalities.4,5 Similar results have been reproduced outside of a large clinical trial, even at the level of a single institution. Furthermore, there is a clear relationship between distinct patient characteristics and their preference and choice with regards to screening methods and prenatal diagnosis.6–8 As a result, the American College of Obstetricians and Gynecologists (ACOG) recommends that all pregnant women should be offered screening for aneuploidy using this new paradigm of first- and second-trimester screening.9

Although such testing is now undergoing widespread implementation, virtually all data regarding these newer screening modalities come from large tertiary care centers. However, the majority (65%) of deliveries in the United States occur in nontertiary hospitals,10 perhaps indicating that most prenatal care occurs in community hospitals. The question remains whether the results from tertiary centers, which may be prone to types of bias, can be generalized to community settings and whether there are performance-related issues affecting the success or failure of such initiatives. The purpose of this study is to review our experience with implementing a new first- and second-trimester screening program for aneuploidy at a community hospital and to report any associated problems or difficulties that were encountered. The objective of this study was to compare clinical outcomes during the first year of the new screening program with those from the time period immediately preceding its implementation.

METHODS

After approval by the Institutional Review Board at the Cleveland Clinic, the electronic medical records of consecutive pregnant patients referred to one board-certified specialist in maternal–fetal medicine (E.H.P.) for genetic counseling from May 17, 2005, through December 31, 2006, at Hillcrest Hospital were reviewed. Hillcrest Hospital, located in the eastern suburbs of Cleveland, Ohio, is a level 2 community hospital with approximately 3,700 deliveries per year.

Data were divided into two groups representing two time periods. The first group included those patients who received traditional genetic screening or testing (pre–nuchal translucency), which consisted of the 7 months immediately before initiation of the new first- and second-trimester screening program. This time period began in May 2005 when the maternal–fetal medicine service expanded to the community hospital. All patients received an extensive genetic counseling session that provided information and education in a nondirective, nonjudgmental manner. Patient options were presented (along with descriptions of limits, risks, and benefits), which included no further testing, quad screening at the appropriate gestational age, a detailed fetal anatomy ultrasound examination performed in the maternal–fetal medicine specialist’s office, and invasive testing by chorionic villus sampling (CVS) and amniocentesis. The second group (nuchal translucency) began with the new screening program on January 1, 2006, shortly after the large clinical trial was published.5 This period ended on December 31, 2006. The genetic counseling session was exactly the same as in the pre–nuchal translucency group except for the addition of a patient brochure, handout, and a 12-minute video in English explaining the new first- and second-trimester screening program in detail. The video was created by the principal investigator (E.H.P.) and was shown to each patient before the counseling session. This video was also placed on the internet so that it could be reviewed before the office visit or at anytime thereafter. After patients viewed the video, the counseling session continued in a similar manner as with the pre–nuchal translucency group. Questions were answered, and patient options were offered.

The new screening program consisted of nuchal translucency measurement and serum biochemical testing. All nuchal translucency measurements were obtained by a sonologist and the same nuchal translucency–certified maternal–fetal medicine specialist according to the standards established by the Maternal-Fetal Medicine Foundation.5 If an accurate measurement was obtained that was less than 3 mm, the patient was offered biochemical testing. If the measurement was greater than or equal to 3 mm or if there was a cystic hygroma or other anomaly suspected, chorionic villus sampling or amniocentesis was offered. In cases where the nuchal translucency measurement could not be accurately obtained, the patient was offered the choice of serum integrated screening or returning on another day to attempt the measurement again. The new screening program initially consisted of only the integrated test that combined the first- and second-trimester results into one second-trimester result. After 4 months, the sequential screening test became commercially available, and this was offered in addition to the integrated screening test. The sequential screening program consisted of obtaining a first- and second-trimester risk assessment—both of which were available to the patient. Serum biochemical testing including pregnancy-associated plasma protein A, total human chorionic gonadotropin, and the quad screen was performed by only one laboratory (Genzyme Genetics, Santa Fe, NM). All patients were informed that the risk assessment results from the screening tests would be in numerical form related to their a priori age-related risk and that these results would be communicated to them as soon as they became available.

Maternal characteristics including age, parity, ethnicity, family and obstetrical history, gestational age and reason for genetic referral, risk assessment for aneuploidy for trisomy 21 or 18, nuchal translucency during the screening program, and patient choice of intervention were collected. The outcome of each patient’s choice also was recorded.

Univariable analyses were displayed by using contingency table analysis. A χ2 or Fisher exact test were used for categorical variables and Student t test for continuous variables. Unadjusted odds ratios are reported using 95% confidence intervals. Data were analyzed using JMP 6.0 (SAS Institute Inc., Cary, NC). A P value of less than .05 was considered to be significant.

RESULTS

A total of 101 patients were referred for genetic counseling during the pre–nuchal translucency period and 359 patients during the nuchal translucency period. There were no differences in the maternal characteristics between the groups (Table 1). The majority of the patients were Caucasian, and all had some form of medical insurance. Advanced maternal age (35 years old or older) was the most common indication for referral in both groups (81% versus 82%) (Table 2). Patients in the pre–nuchal translucency group were more likely to be referred for an abnormal quad screen (10% versus 3%, P=.003) and less likely to be referred for an “unknown reason” (0% versus 16%. P=.003) compared with the nuchal translucency group. After the counseling session, all patients had a detailed fetal anatomy ultrasound examination. Twenty-four (24%) patients in the pre-nuchal translucency group and 23 (6%) in the nuchal translucency group declined any further genetic testing.

Table 1
Table 1:
Maternal Characteristics of Patients Undergoing Traditional and Early Aneuploidy Screening Using Nuchal Translucency
Table 2
Table 2:
Indications for Genetic Referral of Patients Undergoing Traditional and Early Aneuploidy Screening Using Nuchal Translucency

Although there were no differences in maternal age or parity between those patients who chose to have an invasive procedure and those who did not, 46% of patients in the nuchal translucency group underwent an invasive procedure compared with 76% in the pre–nuchal translucency group (odds ratio 0.26, 95% confidence interval 0.15 to 0.42; P<.001). In the nuchal translucency group, there were 127 CVS and 37 amniocentesis procedures compared with 61 CVS and 16 amniocenteses procedures in the pre–nuchal translucency group. Abnormalities in the pre–nuchal translucency group included three cases of trisomy 21, one trisomy 18, one unbalanced translocation, one 48 XX+, one fragile X carrier, one Norrie’s syndrome, and one confined placental mosaicism. Abnormalities in the nuchal translucency group included seven cases of trisomy 21, one trisomy 18, two unbalanced translocations, three balanced translocations, one Turner syndrome, and three confined placental mosaicism.

In the nuchal translucency group, the a priori age risk of aneuploidy was compared with the screening results (Table 3). For those patients whose risk of both trisomy 21 and 18 decreased, there were five patients who decided to proceed with invasive testing (four CVS and one amniocentesis). There were seven patients whose risk of both trisomy 21 and 18 increased. Chorionic villus sampling was performed in five patients. The remaining two patients declined further genetic testing. There were 13 patients whose risk of trisomy 21 increased and risk of trisomy 18 decreased. Chorionic villus sampling was performed in three patients, and an amniocentesis was performed in four patients. Six patients declined further genetic testing. There was one patient where the risk of trisomy 21 decreased and the risk of trisomy 18 increased. This patient had a genetic amniocentesis.

Table 3
Table 3:
The A Priori Age Risk of Aneuploidy Compared With the Screening Results and Further Testing in the Nuchal Translucency Group

DISCUSSION

The purpose of this study was to review our initial experience with a new first- and second-trimester screening program for aneuploidy in the setting of a single community hospital. The key finding of this study was the 30% reduction in the number of invasive procedures for prenatal diagnosis performed during the first year of this initiative, while maintaining an acceptable detection rate. Despite its increased complexity, these newer screening modalities seemed to be widely accepted and highly regarded by both the patients and their referring physicians.

One possible explanation for this dramatic decrease in invasive procedures could be that more patients were willing to undergo aneuploidy screening to assess their risk rather than to proceed with an invasive procedure. More patients were referred to our new program as a result of reporting in the press and the promotional and advertising activities by companies. The decrease in invasive procedures also could have been related to the additional educational material, including the new brochure and video. Patients may have chosen this new paradigm because they may have been better informed with more options. Nevertheless, previous trials have reported a reduction in invasive procedures, particularly with CVS. Perni et al reported, after implementation of first-trimester screening for aneuploidy, a decrease from 70% to 64.7% in all patients of advanced maternal age who opted for prenatal diagnosis.6 The decrease was most notable among women between the ages of 35 and 39 years, with a reduction from 67.7% to 60.1%. Conversely, for women 40 years of age or older, the rate of invasive testing actually increased from 78.9% to 83%. In another study1 demonstrating the benefit and value of such screening programs, the percentage of patients opting for prenatal diagnosis after a positive screen (greater than or equal to a 1 in 300 risk for Down syndrome) was 77.6%, whereas the rate of invasive testing among patients who screened negative (less than a 1 in 300 risk for Down syndrome) was only 4.6%. Our data, although comparable, were obtained at a single center where the majority of the patients are well educated, privately insured, and Caucasian. Thus, application of our results to all populations and centers may not be appropriate.

Our program was created with paramount importance given to ethical principles such as benevolence and autonomy. Informed consent and nondirective genetic counseling were at the core of maintaining adherence to these standards. Patients were continuously updated as to changes in our screening policies and the options available to them. Interestingly, with the introduction of sequential screening, the majority of patients opted for this paradigm instead of the traditional integrated screen in which results are not disclosed until the completion of the second-trimester testing. Our study also illustrates that decisions regarding screening and prenatal diagnosis are not always linked to each other. Some patients opted to proceed with prenatal diagnosis despite reassuring screening results, whereas others declined prenatal diagnosis even though their a priori risk increased. Thus, any screening program that is to be implemented needs to maintain some degree of flexibility and be supportive of each individual’s decisions.

Finally, our study also demonstrated the need for better informational and educational materials. A new brochure and video were created to address this issue and seemed to work well toward this purpose regarding the screening program. For many patients who had experienced false-positive quad screening in a previous pregnancy, the lower false positive rate with the new screening test and no invasive testing was sufficient for prenatal diagnosis. The executive summary of the National Institute of Child Health and Human Development workshop report supports implementing first-trimester Down syndrome risk assessment, providing certain requirements are met. These include training and quality control standards, access to chorionic villus sampling, and appropriate counseling regarding screening options.11 All of these criteria for implementation are available in our institution. However, our program needed additional office support for the increase in the number of patients wanting to participate in the new program and for communicating the results to the patient and her obstetrical provider. Our results support the recent ACOG guidelines recommending that all pregnant women could be offered less invasive screening, but resources for patient access, patient choice, and reporting are also necessary for any first- and second-trimester program to be successful.

REFERENCES

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© 2008 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.