class RegisterForm(Form):
    username = StringField('Username', validators=[DataRequired(), Length(min=3, max=25)])
    email = StringField('Email', validators=[DataRequired(), Email(), Length(min=6, max=40)])
    password = PasswordField('Password', validators=[DataRequired(), Length(min=6, max=40)])

{% from "macros.html" import render_field  %}
<div class="container-narrow">
<h1>Register</h1>
<br/>
<form id="registerForm" class="form form-register" method="POST" action="" role="form">
        {{ form.hidden_tag() }}
        {% for field in form %}
            {% print(field.label != 'Email')%}
            {% print(field.label)%}
            {% print(field.name)%}
            {% if field.label!='Email' or email=='False' %}
                {{ render_field(field) }}
            {% endif %}
        {% endfor %}
        <p><input class="btn btn-default btn-submit" type="submit" value="Register"></p>
</form>
{% endblock %}

{% macro render_field(field)%}

<div class="form-group">
{#                {{field.label}}#}
                {{field(placeholder=field.label.text, class_="form-control")}}
</div>

{% endmacro %}

{% print(field.label != 'Email')%}